]> Linux IPv6 HOWTO (en) Peter Bieringer
pb at bieringer.de
Release 0.44 2003-08-15 PB See revision history for more Release 0.43 2003-06-05 PB See revision history for more Release 0.42 2003-05-09 PB See revision history for more The goal of the Linux IPv6 HOWTO is to answer both basic and advanced questions about IPv6 on the Linux operating system. This HOWTO will provide the reader with enough information to install, configure, and use IPv6 applications on Linux machines. General CVS-ID: $Id: Linux+IPv6-HOWTO.lyx,v 1.81 2003/09/06 07:22:59 pbldp Exp $ Information about available translations you will find in section Translations. Copyright, license and others Copyright Written and Copyright (C) 2001-2003 by Peter Bieringer License This Linux IPv6 HOWTO is published under GNU GPL version 2: The Linux IPv6 HOWTO, a guide how to configure and use IPv6 on Linux systems. Copyright (C) 2001-2003 Peter Bieringer This documentation is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 2 of the License, or (at your option) any later version. This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with this program; if not, write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. About the author Internet/IPv6 history of the author 1993: I got in contact with the Internet using console based e-mail and news client (e.g. look for "e91abier" on groups.google.com, that's me). 1996: I got a request for designing a course on IPv6, including a workshop with the Linux operating system. 1997: Started writing a guide on how to install, configure and use IPv6 on Linux systems, called IPv6 & Linux - HowTo (see IPv6 & Linux - HowTo/History for more information). 2001: Started writing this new Linux IPv6 HOWTO. Contact The author can be contacted via e-mail at <pb at bieringer dot de> and also via his homepage. He's currently living in Munich [northern part of Schwabing] / Bavaria / Germany (south) / Europe (middle) / Earth (surface/mainland). Category This HOWTO should be listed in category "Networking/Protocols". Version, History and To-Do Version The current version is shown above. History Major history 2001-11-30: Starting to design new HOWTO. 2002-01-02: A lot of content completed, first public release of chapter 1 (version 0.10). 2002-01-14: More completed, some reviews, public release of the whole document (version 0.14). 2002-08-16: Polish translation is in progress 2002-10-31: Chinese translation is available (see Translations for more) 2002-11-10: German translation is in progress 2003-02-10: German translation is available 2003-04-09: French translation is in progress 2003-05-09: French translation is available 2003-08-15: Spanish translation is in progress Full history See revision history at the end of this document. To-Do Fill in missing content Finishing grammar checking Translations Translations always have to contain the URL, version number and copyright of the original document (but yours, too). Pls. don't translate the original changelog, this is not very useful. Looks like the document's change frequency is mostly less than once per month. Since version 0.27 it looks like that most of the content contributed by me has been written. Translations always have to use the English version as source. To language Taiwanese A Taiwanese translation by Burma Chen <expns at yahoo dot com> (announced to me at 2002-10-31) can be found on the CLDP: http://cldp.linuxforum.net/Linux-IPv6-HOWTO.html. It's a snapshot translation, don't know whether kept up-to-date. Polish Since 2002-08-16 a Polish translation was started and is still in progress by Lukasz Jokiel <Lukasz dot Jokiel at klonex dot com dot pl>. Taken source: CVS-version 1.29 of LyX file, which was source for howto version 0.27. German With 2002-11-10 a German translation was started by Georg Käfer <gkaefer at gmx dot at> and the first public version was published 2003-02-10. It's originally available on Deep Space 6 at http://mirrors.deepspace6.net/Linux+IPv6-HOWTO-de/ (mirrored e.g. on http://mirrors.bieringer.de/Linux+IPv6-HOWTO-de/). This version will stay up-to-date as much as possible. French With 2003-04-09 a French translation was started by Michel Boucey <mboucey at free dot fr> and the first public version was published 2003-05-09. It's originally available on Deep Space 6 at http://mirrors.deepspace6.net/Linux+IPv6-HOWTO-fr/ (mirrored e.g. on http://mirrors.bieringer.de/Linux+IPv6-HOWTO-fr/). Spanish With 2003-08-15 a Spanish translation was started by Eduardo Collado <edu at eduangi dot com>. Japanese On 2003-05-14 Shino Taketani <shino_1305 at hotmail dot com> send me a note that he planned to translate the HowTo into Japanese. Technical Original source of this HOWTO This HOWTO is currently written with LyX version 1.2.0 on a Red Hat Linux 7.3 system with template SGML (DocBook book). It's available on TLDP-CVS / users / Peter-Bieringer for contribution. Code line wrapping Code line wrapping is done using selfmade utility "lyxcodelinewrapper.pl", you can get it from CVS for your own usage: TLDP-CVS / users / Peter-Bieringer SGML generation SGML is generated using export function in LyX. Also some fixes are have to be made to create proper SGML code (see also here for the Perl programs TLDP-CVS / users / Peter-Bieringer): Export of LyX table does not create proper "colspan" tags - tool for fixing: "sgmllyxtabletagfix.pl" (fixed since LyX 1.2.0) LyX sometimes uses special left/right entities for quotes instead the normal one, which will still exist in generated HTML. Some browsers don't parse this very well (known: Opera 6 TP 2 or Konqueror) - tool for fixing: "sgmllyxquotefix.pl" On-line references to the HTML version of this HOWTO (linking/anchors) Master index page Generally, a reference to the master index page is recommended. Dedicated pages Because the HTML pages are generated out of the SGML file, the HTML filenames turn out to be quite random. However, some pages are tagged in LyX, resulting in static names. These tags are useful for references and shouldn't be changed in the future. If you think that I have forgotten a tag, please let me know, and I will add it. Preface Some things first: How many versions of a Linux & IPv6 related HOWTO are floating around? Including this, there are three (3) HOWTO documents available. Apologies, if that is too many ;-) Linux IPv6 FAQ/HOWTO (outdated) The first IPv6 related document was written by Eric Osborne and called Linux IPv6 FAQ/HOWTO (please use it only for historical issues). Latest version was 3.2.1 released July, 14 1997. Please help: if someone knows the date of birth of this HOWTO, please send me an e-mail (information will be needed in "history"). IPv6 & Linux - HowTo (maintained) This HOWTO is really named "HowTo" There exists a second version called IPv6 & Linux - HowTo written by me (Peter Bieringer) in pure HTML. It was born April 1997 and the first English version was published in June 1997. I will continue to maintain it, but it will slowly fade (but not full) in favour of the Linux IPv6 HOWTO you are currently reading. Linux IPv6 HOWTO (this document) Because the IPv6 & Linux - HowTo is written in pure HTML it's not really compatible with the The Linux Documentation Project (TLDP). I (Peter Bieringer) got a request in late November 2001 to rewrite the IPv6 & Linux - HowTo in SGML. However, because of the discontinuation of that HOWTO (Future of IPv6 & Linux - HowTo), and as IPv6 is becoming more and more standard, I decided to write a new document covering basic and advanced issues which will remain important over the next few years. More dynamic and some advanced content will be still found further on in the second HOWTO (IPv6 & Linux - HowTo). Used terms, glossar and shortcuts Network related Base 10 Well known decimal number system, represent any value with digit 0-9. Base 16 Usually used in lower and higher programming languages, known also as hexadecimal number system, represent any value with digit 0-9 and char A-F (case insensitive). Base 85 Representation of a value with 85 different digits/chars, this can lead to shorter strings but never seen in the wild. Bit Smallest storage unit, on/true (1) or off/false (0) Byte Mostly a collection of 8 (but not really a must - see older computer systems) bits Device Here, hardware of network connection, see also NIC Dual homed host A dual homed host is a node with two network (physical or virtual) interfaces on two different links, but does not forward any packets between the interfaces. Host Generally a single homed host on a link. Normally it has only one active network interface, e.g. Ethernet or (not and) PPP. Interface Mostly same as "device", see also NIC IP Header Header of an IP packet (each network packet has a header, kind of is depending on network layer) Link A link is a layer 2 network packet transport medium, examples are Ethernet, Token Ring, PPP, SLIP, ATM, ISDN, Frame Relay,... Node A node is a host or a router. Octets A collection of 8 real bits, today also similar to "byte". Port Information for the TCP/UDP dispatcher (layer 4) to transport information to upper layers Protocol Each network layer contains mostly a protocol field to make life easier on dispatching transported information to upper layer, seen in layer 2 (MAC) and 3 (IP) Router A router is a node with two or more network (physical or virtual) interfaces, capable of forwarding packets between the interfaces. Socket An IP socket is defined by source and destination IP addresses and Ports and (binding) Stack Network related a collection of layers Subnetmask IP networks uses bit masks to separate local networks from remote ones Tunnel A tunnel is typically a point-to-point connection over which packets are exchanged which carry the data of another protocol, e.g. an IPv6-in-IPv4 tunnel. Shortcuts ACL Access Control List API Application Programming Interface ASIC Application Specified Integrated Circuit BSD Berkeley Software Distribution CAN-Bus Controller Area Network Bus (physical bus system) KAME Project - a joint effort of six companies in Japan to provide a free IPv6 and IPsec (for both IPv4 and IPv6) stack for BSD variants to the world www.kame.net NIC Network Interface Card RFC Request For Comments - set of technical and organizational notes about the Internet USAGI UniverSAl playGround for Ipv6 Project - works to deliver the production quality IPv6 protocol stack for the Linux system. Document related Long code line wrapping signal char The special character "¬" is used for signaling that this code line is wrapped for better viewing in PDF and PS files. Placeholders In generic examples you will sometimes find the following: ]]> For real use on your system command line or in scripts this has to be replaced with relevant content (removing the < and > of course), the result would be e.g. Commands in the shell Commands executable as non-root user begin with $, e.g. Commands executable as root user begin with #, e.g. Requirements for using this HOWTO Personal prerequisites Experience with Unix tools You should be familiar with the major Unix tools e.g. grep, awk, find, ... , and know about their most commonly used command-line options. Experience with networking theory You should know about layers, protocols, addresses, cables, plugs, etc. If you are new to this field, here is one good starting point for you: linuxports/howto/intro_to_networking Experience with IPv4 configuration You should definitely have some experience in IPv4 configuration, otherwise it will be hard for you to understand what is really going on. Experience with the Domain Name System (DNS) Also you should understand what the Domain Name System (DNS) is, what it provides and how to use it. Experience with network debugging strategies You should at least understand how to use tcpdump and what it can show you. Otherwise, network debugging will very difficult for you. Linux operating system compatible hardware Surely you wish to experiment with real hardware, and not only read this HOWTO to fall asleep here and there. ;-7) Basics What is IPv6? IPv6 is a new layer 3 protocol (see linuxports/howto/intro_to_networking/ISO - OSI Model) which will supersede IPv4 (also known as IP). IPv4 was designed long time ago (RFC 760 / Internet Protocol from January 1980) and since its inception, there have been many requests for more addresses and enhanced capabilities. Latest RFC is RFC 2460 / Internet Protocol Version 6 Specification. Major changes in IPv6 are the redesign of the header, including the increase of address size from 32 bits to 128 bits. Because layer 3 is responsible for end-to-end packet transport using packet routing based on addresses, it must include the new IPv6 addresses (source and destination), like IPv4. For more information about the IPv6 history take a look at older IPv6 related RFCs listed e.g. at SWITCH IPv6 Pilot / References. History of IPv6 in Linux The years 1992, 1993 and 1994 of the IPv6 History (in general) are covered by following document: IPv6 or IPng (IP next generation). To-do: better time-line, more content... Beginning The first IPv6 related network code was added to the Linux kernel 2.1.8 in November 1996 by Pedro Roque. It was based on the BSD API: ]]> ]]> The shown lines were copied from patch-2.1.8 (e-mail address was blanked on copy&paste). In between Because of lack of manpower, the IPv6 implementation in the kernel was unable to follow the discussed drafts or newly released RFCs. In October 2000, a project was started in Japan, called USAGI, whose aim was to implement all missing, or outdated IPv6 support in Linux. It tracks the current IPv6 implementation in FreeBSD made by the KAME project. From time to time they create snapshots against current vanilla Linux kernel sources. Current Unfortunately, the USAGI patch is so big, that current Linux networking maintainers are unable to include it in the production source of the Linux kernel 2.4.x series. Therefore the 2.4.x series is missing some (many) extensions and also does not confirm to all current drafts and RFCs (see IP Version 6 Working Group (ipv6) Charter). This can cause some interoperability problems with other operating systems. Future USAGI is now making use of the new Linux kernel development series 2.5.x to insert all of their current extensions into this development release. Hopefully the 2.6.x kernel series will contain a true and up-to-date IPv6 implementation. How do IPv6 addresses look like? As previously mentioned, IPv6 addresses are 128 bits long. This number of bits generates very high decimal numbers with up to 39 digits: Such numbers are not really addresses that can be memorized. Also the IPv6 address schema is bitwise orientated (just like IPv4, but that's not often recognized). Therefore a better notation of such big numbers is hexadecimal. In hexadecimal, 4 bits (also known as "nibble") are represented by a digit or character from 0-9 and a-f (10-15). This format reduces the length of the IPv6 address to 32 characters. This representation is still not very convenient (possible mix-up or loss of single hexadecimal digits), so the designers of IPv6 chose a hexadecimal format with a colon as separator after each block of 16 bits. In addition, the leading "0x" (a signifier for hexadecimal values used in programming languages) is removed: A usable address (see address types later) is e.g.: For simplifications, leading zeros of each 16 bit block can be omitted: ]]> One sequence of 16 bit blocks containing only zeroes can be replaced with "::". But not more than one at a time, otherwise it is no longer a unique representation. 3ffe:ffff:100:f101::1 ]]> The biggest reduction is seen by the IPv6 localhost address: ::1 ]]> There is also a so-called compact (base85 coded) representation defined RFC 1924 / A Compact Representation of IPv6 Addresses (published on 1. April 1996), never seen in the wild, probably an April fool's joke, but here is an example: J%s99FJXT ]]>
Info: ipv6calc is an IPv6 address format calculator and converter program and can be found here: ipv6calc homepage (Mirror)
FAQ (Basics) Why is the name IPv6 and not IPv5 as successor for IPv4? On any IP header, the first 4 bits are reserved for protocol version. So theoretically a protocol number between 0 and 15 is possible: 4: is already used for IPv4 5: is reserved for the Stream Protocol (STP, RFC 1819 / Internet Stream Protocol Version 2) (which never really made it to the public) The next free number was 6. Hence IPv6 was born! IPv6 addresses: why such a high number of bits? During the design of IPv4, people thought that 32 bits were enough for the world. Looking back into the past, 32 bits were enough until now and will perhaps be enough for another few years. However, 32 bits are not enough to provide each network device with a global address in the future. Think about mobile phones, cars (including electronic devices on its CAN-bus), toasters, refrigerators, light switches, and so on... So designers have chosen 128 bits, 4 times more in length and 2^96 greater in size than in IPv4 today. The usable size is smaller than it may appear however. This is because in the currently defined address schema, 64 bits are used for interface identifiers. The other 64 bits are used for routing. Assuming the current strict levels of aggregation (/48, /35, ...), it is still possible to "run out" of space, but hopefully not in the near future. See also for more information RFC 1715 / The H Ratio for Address Assignment Efficiency and RFC 3194 / The Host-Density Ratio for Address Assignment Efficiency. IPv6 addresses: why so small a number of bits on a new design? While, there are (possibly) some people (only know about Jim Fleming...) on the Internet who are thinking about IPv8 and IPv16, their design is far away from acceptance and implementation. In the meantime 128 bits was the best choice regarding header overhead and data transport. Consider the minimum Maximum Transfer Unit (MTU) in IPv4 (576 octets) and in IPv6 (1280 octets), the header length in IPv4 is 20 octets (minimum, can increase to 60 octets with IPv4 options) and in IPv6 is 48 octets (fixed). This is 3.4 % of MTU in IPv4 and 3.8 % of MTU in IPv6. This means the header overhead is almost equal. More bits for addresses would require bigger headers and therefore more overhead. Also, consider the maximum MTU on normal links (like Ethernet today): it's 1500 octets (in special cases: 9k octets using Jumbo frames). Ultimately, it wouldn't be a proper design if 10 % or 20 % of transported data in a Layer-3 packet were used for addresses and not for payload. Address types Like IPv4, IPv6 addresses can be split into network and host parts using subnet masks. IPv4 has shown that sometimes it would be nice, if more than one IP address can be assigned to an interface, each for a different purpose (aliases, multi-cast). To remain extensible in the future, IPv6 is going further and allows more than one IPv6 address to be assigned to an interface. There is currently no limit defined by an RFC, only in the implementation of the IPv6 stack (to prevent DoS attacks). Using this large number of bits for addresses, IPv6 defines address types based on some leading bits, which are hopefully never going to be broken in the future (unlike IPv4 today and the history of class A, B, and C). Also the number of bits are separated into a network part (upper 64 bits) and a host part (lower 64 bits), to facilitate auto-configuration. BTW: a good URL for displaying a given IPv6 address in detail is the Advanced Network Management Laboratory / IPv6 Address Oracle. Addresses without a special prefix Localhost address This is a special address for the loopback interface, similiar to IPv4 with its "127.0.0.1". With IPv6, the localhost address is: or compressed: Packets with this address as source or destination should never leave the sending host. Unspecified address This is a special address like "any" or "0.0.0.0" in IPv4 . For IPv6 it's: or: These addresses are mostly used/seen in socket binding (to any IPv6 address) or routing tables. Note: the unspecified address cannot be used as destination address. IPv6 address with embedded IPv4 address There are two addresses which contain an IPv4 address. IPv4-mapped IPv6 address IPv4-only IPv6-compatible addresses are sometimes used/shown for sockets created by an IPv6-enabled daemon, but only binding to an IPv4 address. These addresses are defined with a special prefix of length 96 (a.b.c.d is the IPv4 address): or in compressed format For example, the IPv4 address 1.2.3.4 looks like this: IPv4-compatible IPv6 address Used for automatic tunneling (RFC 2893 / Transition Mechanisms for IPv6 Hosts and Routers), which is being replaced by 6to4 tunneling. or in compressed format Network part, also known as prefix Designers defined some address types and left a lot of scope for future definitions as currently unknown requirements arise. RFC 2373 [July 1998] / IP Version 6 Addressing Architecture defines the current addressing scheme but there is already a new draft available: draft-ietf-ipngwg-addr-arch-*.txt. Now lets take a look at the different types of prefixes (and therefore address types): Link local address type These are special addresses which will only be valid on a link of an interface. Using this address as destination the packet would never pass through a router. It's used for link communications such as: anyone else here on this link? anyone here with a special address (e.g. looking for a router)? They begin with ( where "x" is any hex character, normally "0") An address with this prefix is found on each IPv6-enabled interface after stateless auto-configuration (which is normally always the case). Site local address type These are addresses similar to the RFC 1918 / Address Allocation for Private Internets in IPv4 today, with the added advantage that everyone who use this address type has the capability to use the given 16 bits for a maximum number of 65536 subnets. Comparable with the 10.0.0.0/8 in IPv4 today. Another advantage: because it's possible to assign more than one address to an interface with IPv6, you can also assign such a site local address in addition to a global one. It begins with: (where "x" is any hex character, normally "0") Global address type "(Aggregatable) global unicast" Today, there is one global address type defined (the first design, called "provider based," was thrown away some years ago RFC 1884 / IP Version 6 Addressing Architecture [obsolete], you will find some remains in older Linux kernel sources). It begins with (x are hex characters) Note: the prefix "aggregatable" is thrown away in current drafts. There are some further subtypes defined, see below: 6bone test addresses These were the first global addresses which were defined and in use. They all start with Example: A special 6bone test address which will be never be globally unique begins with and is mostly shown in examples, because if real addresses are shown, its possible for someone to do a copy & paste to their configuration files. Thus inadvertently causing duplicates on a globally unique address. This would cause serious problems for the original host (e.g. getting answer packets for request that were never sent). You can still apply for one of these prefixes, see here How to join 6bone. Also some tunnel brokers still distribute 6bone test address prefixes. 6to4 addresses These addresses, designed for a special tunneling mechanism [RFC 3056 / Connection of IPv6 Domains via IPv4 Clouds and RFC 2893 / Transition Mechanisms for IPv6 Hosts and Routers], encode a given IPv4 address and a possible subnet and begin with For example, representing 192.168.1.1/5: A small shell command line can help you generating such address out of a given IPv4 one: See also tunneling using 6to4 and information about 6to4 relay routers. Assigned by provider for hierarchical routing These addresses are delegated to Internet service providers (ISP) and begin with Prefixes to major (backbone owning) ISPs are delegated by local registries and currently they assign to them a prefix with length 35. Major ISPs normally delegate to minor ISPs a prefix with length 48. Multicast addresses Multicast addresses are used for related services. They alway start with (xx is the scope value) They are split into scopes and types: Multicast scopes Multicast scope is a parameter to specify the maximum distance a multicast packet can travel from the sending entity. Currently, the following regions (scopes) are defined: ffx1: node-local, packets never leave the node. ffx2: link-local, packets are never forwarded by routers, so they never leave the specified link. ffx5: site-local, packets never leave the site. ffx8: organization-local, packets never leave the organization (not so easy to implement, must be covered by routing protocol). ffxe: global scope. others are reserved Multicast types There are many types already defined/reserved (see RFC 2373 / IP Version 6 Addressing Architecture for details). Some examples are: All Nodes Address: ID = 1h, addresses all hosts on the local node (ff01:0:0:0:0:0:0:1) or the connected link (ff02:0:0:0:0:0:0:1). All Routers Address: ID = 2h, addresses all routers on the local node (ff01:0:0:0:0:0:0:2), on the connected link (ff02:0:0:0:0:0:0:2), or on the local site (ff05:0:0:0:0:0:0:2) Solicited node link-local multicast address Special multicast address used as destination address in neighborhood discovery, because unlike in IPv4, ARP no longer exists in IPv6. An example of this address looks like Used prefix shows that this is a link-local multicast address. The suffix is generated from the destination address. In this example, a packet should be sent to address "fe80::1234", but the network stack doesn't know the current layer 2 MAC address. It replaces the upper 104 bits with "ff02:0:0:0:0:1:ff00::/104" and leaves the lower 24 bits untouched. This address is now used `on-link' to find the corresponding node which has to send a reply containing its layer 2 MAC address. Anycast addresses Anycast addresses are special addresses and are used to cover things like nearest DNS server, nearest DHCP server, or similar dynamic groups. Addresses are taken out of the unicast address space (aggregatable global or site-local at the moment). The anycast mechanism (client view) will be handled by dynamic routing protocols. Note: Anycast addresses cannot be used as source addresses, they are only used as destination addresses. Subnet-router anycast address A simple example for an anycast address is the subnet-router anycast address. Assuming that a node has the following global assigned IPv6 address: The subnet-router anycast address will be created blanking the suffix (least significant 64 bits) completely: Address types (host part) For auto-configuration and mobility issues, it was decided to use the lower 64 bits as host part of the address in most of the current address types. Therefore each single subnet can hold a large amount of addresses. This host part can be inspected differently: Automatically computed (also known as stateless) With auto-configuration, the host part of the address is computed by converting the MAC address of an interface (if available), with the EUI-64 method, to a unique IPv6 address. If no MAC address is available for this device (happens e.g. on virtual devices), something else (like the IPv4 address or the MAC address of a physical interface) is used instead. Consider again the first example here, is the host part and computed from the NIC's MAC address using the IEEE-Tutorial EUI-64 design for EUI-48 identifiers. Privacy problem with automatically computed addresses and a solution Because the "automatically computed" host part is globally unique (except when a vendor of a NIC uses the same MAC address on more than one NIC), client tracking is possible on the host when not using a proxy of any kind. This is a known problem, and a solution was defined: privacy extension, defined in RFC 3041 / Privacy Extensions for Stateless Address Autoconfiguration in IPv6 (there is also already a newer draft available: draft-ietf-ipngwg-temp-addresses-*.txt). Using a random and a static value a new suffix is generated from time to time. Note: this is only reasonable for outgoing client connections and isn't really useful for well-known servers. Manually set For servers it's probably easier to remember simpler addresses, this can also be accommodated. It is possible to assign an additional IPv6 address to an interface, e.g. For manual suffixes like "::1" shown in the above example it's required that the 6th most significant bit is set to 0 (the universal/local bit of the automatically generated identifier). Also some other (otherwise unchosen ) bit combinations are reserved for anycast addresses, too. Prefix lengths for routing In the early design phase it was planned to use a fully hierarchical routing approach to reduce the size of the routing tables maximally. The reasoning behind this approach were the number of current IPv4 routing entries in core routers (> 104 thousand in May 2001), reducing the need of memory in hardware routers (ASIC "Application Specified Integrated Circuit" driven) to hold the routing table and increase speed (fewer entries hopefully result in faster lookups). Todays view is that routing will be mostly hierarchically designed for networks with only one service provider. With more than one ISP connections, this is not possible, and subject to an issue named multi-homing (infos on multi-homing: Procider-Internal Aggregation based on Geography to Support Multihoming in IPv6; GAPI: A Geographically Aggregatable Provider Independent Address Space to Support Multihoming in IPv6; Extension Header for Site-Multi-homing support; IPv6 Multihoming Solutions) Prefix lengths (also known as "netmasks") Similar to IPv4, the routable network path for routing to take place. Because standard netmask notation for 128 bits doesn't look nice, designers employed the IPv4 Classless Inter Domain Routing (CIDR, RFC 1519 / Classless Inter-Domain Routing) scheme, which specifies the number of bits of the IP address to be used for routing. It is also called the "slash" notation. An example: This notation will be expanded: Network: Netmask: Matching a route Under normal circumstances (no QoS) a lookup in a routing table results in the route with the most significant number of address bits means the route with the biggest prefix length matches first. For example if a routing table shows following entries (list is not complete): Shown destination addresses of IPv6 packets will be routed through shown device routed through device sit1 ]]> routed through device tun6to4 ]]> IPv6-ready system check Before you can start using IPv6 on a Linux host, you have to test, whether your system is IPv6-ready. You may have to do some work to enable it first. IPv6-ready kernel Modern Linux distributions already contain IPv6-ready kernels, the IPv6 capability is generally compiled as a module, but it's possible that this module is not loaded automatically on startup. See IPv6+Linux-Status-Distribution page for most up-to-date information. Note: you shouldn't anymore use kernel series 2.2.x, because it's not IPv6-up-to-date anymore. Check for IPv6 support in the current running kernel To check, whether your current running kernel supports IPv6, take a look into your /proc-file-system. Following entry must exists: A short automatical test looks like: If this fails, it is quite likely, that the IPv6 module is not loaded. Try to load IPv6 module You can try to load the IPv6 module executing If this is successful, this module should be listed, testable with following auto-magically line: And the check shown above should now run successfully. Note: unloading the module is currently not supported and can result, under some circumstances, in a kernel crash. Automatically loading of module Its possible to automatically load the IPv6 module on demand. You only have to add following line in the configuration file of the kernel module loader (normally /etc/modules.conf or /etc/conf.modules): It's also possible to disable automatically loading of the IPv6 module using following line Additional note: in future kernels (newer 2.5 series and above), the module loader mechanism was changed. The new configuration file has to be named /etc/modprobe.conf instead of /etc/modules.conf but there is a translate-script available. For further details see module-init-tool. Compile kernel with IPv6 capabilities If both above shown results were negative and your kernel has no IP6 support, than you have the following options: Update your distribution to a current one which supports IPv6 out-of-the-box (recommended for newbies), see here again: IPv6+Linux-Status-Distribution Compile a new vanilla kernel (easy, if you know which options you needed) Recompile kernel sources given by your Linux distribution (sometimes not so easy) Compile a kernel with USAGI extensions If you decide to compile a kernel, you should have previous experience in kernel compiling and read the Linux Kernel HOWTO. A mostly up-to-time comparison between vanilla and USAGI extended kernels is available on IPv6+Linux-Status-Kernel. Compiling a vanilla kernel More detailed hints about compiling an IPv6-enabled kernel can be found e.g. on IPv6-HOWTO-2#kernel. Note: you should use whenever possible kernel series 2.4.x or above, because the IPv6 support in series 2.2.x is not so in current state and needs some patches for ICMPv6 and 6to4 support (can be found on kernel series 2.2.x IPv6 patches). Compiling a kernel with USAGI extensions Same as for vanilla kernel, only recommend for advanced users, which are already familiar with IPv6 and kernel compilation. See also USAGI project / FAQ and Obtaining the best IPv6 support with Linux (Article) (Mirror). IPv6-ready network devices Not all existing network devices have already (or ever) the capability to transport IPv6 packets. A current status can be found at IPv6+Linux-status-kernel.html#transport. A major issue is that because of the network layer structure of kernel implementation an IPv6 packet isn't really recognized by it's IP header number (6 instead of 4). It's recognized by the protocol number of the Layer 2 transport protocol. Therefore any transport protocol which doesn't use such protocol number cannot dispatch IPv6 packets. Note: the packet is still transported over the link, but on receivers side, the dispatching won't work (you can see this e.g. using tcpdump). Currently known never "IPv6 capable links" Serial Line IP (SLIP, RFC 1055 / SLIP), should be better called now to SLIPv4, device named: slX Parallel Line IP (PLIP), same like SLIP, device names: plipX ISDN with encapsulation rawip, device names: isdnX Currently known "not supported IPv6 capable links" ISDN with encapsulation syncppp, device names: ipppX (design issue of the ipppd, will be merged into more general PPP layer in kernel series 2.5.x) IPv6-ready network configuration tools You wont get very far, if you are running an IPv6-ready kernel, but have no tools to configure IPv6. There are several packages in existence which can configure IPv6. net-tools package The net-tool package includes some tools like ifconfig and route, which helps you to configure IPv6 on an interface. Look at the output of ifconfig -? or route -?, if something is shown like IPv6 or inet6, then the tool is IPv6-ready. Auto-magically check: & 1|grep -qw 'inet6' && echo "utility 'ifconfig' is ]]> Same check can be done for route: & 1|grep -qw 'inet6' && echo "utility 'route' is IPv6-ready" ]]> iproute package Alexey N. Kuznetsov (current a maintainer of the Linux networking code) created a tool-set which configures networks through the netlink device. Using this tool-set you have more functionality than net-tools provides, but its not very well documented and isn't for the faint of heart. &1 |grep -qw 'inet6' && echo "utility 'ip' is IPv6-ready" ]]> If the program /sbin/ip isn't found, then I strongly recommend you install the iproute package. You can get it from your Linux distribution (if contained) You can download the tar-ball and recompile it: Original FTP source and mirror (missing) You're able to look for a proper RPM package at RPMfind/iproute (sometimes rebuilding of a SRPMS package is recommended) IPv6-ready test/debug programs After you have prepared your system for IPv6, you now want to use IPv6 for network communications. First you should learn how to examine IPv6 packets with a sniffer program. This is strongly recommended because for debugging/troubleshooting issues this can aide in providing a diagnosis very quickly. IPv6 ping This program is normally included in package iputils. It is designed for simple transport tests sending ICMPv6 echo-request packets and wait for ICMPv6 echo-reply packets. Usage ]]> ]]>] ]]> Example Hint: ping6 needs raw access to socket and therefore root permissions. So if non-root users cannot use ping6 then there are two possible problems: ping6 is not in users path (probably, because ping6 is generally stored in /usr/sbin -> add path (not really recommended) ping6 doesn't execute properly, generally because of missing root permissions -> chmod u+s /usr/sbin/ping6 Specifying interface for IPv6 ping Using link-local addresses for an IPv6 ping, the kernel does not know through which (physically or virtual) device it must send the packet - each device has a link-local address. A try will result in following error message: In this case you have to specify the interface additionally like shown here: Ping6 to multicast addresses An interesting mechanism to detect IPv6-active hosts on a link is to ping6 to the link-local all-node multicast address: Unlike in IPv4, where replies to a ping on the broadcast address can be disabled, in IPv6 currently this behavior cannot be disable except by local IPv6 firewalling. IPv6 traceroute6 This program is normally included in package iputils. It's a program similar to IPv4 traceroute. Below you will see an example: Note: unlike some modern versions of IPv4 traceroute, which can use ICMPv4 echo-request packets as well as UDP packets (default), current IPv6-traceroute is only able to send UDP packets. As you perhaps already know, ICMP echo-request packets are more accepted by firewalls or ACLs on routers inbetween than UDP packets. IPv6 tracepath6 This program is normally included in package iputils. It's a program like traceroute6 and traces the path to a given destination discovering the MTU along this path. Below you will see an example: IPv6 tcpdump On Linux, tcpdump is the major tool for packet capturing. Below you find some examples. IPv6 support is normally built-in in current releases of version 3.6. tcpdump uses expressions for filtering packets to minimize the noise: icmp6: filters native ICMPv6 traffic ip6: filters native IPv6 traffic (including ICMPv6) proto ipv6: filters tunneled IPv6-in-IPv4 traffic not port ssh: to suppress displaying SSH packets for running tcpdump in a remote SSH session Also some command line options are very useful to catch and print more information in a packet, mostly interesting for digging into ICMPv6 packets: "-s 512": increase the snap length during capturing of a packet to 512 bytes "-vv": really verbose output "-n": don't resolve addresses to names, useful if reverse DNS resolving isn't working proper IPv6 ping to 3ffe:ffff:100:f101::1 native over a local link 3ffe:ffff:100:f101::1: icmp6: echo ]]> 3ffe:ffff:100:f101:2e0:18ff:fe90:9205: icmp6: echo ]]> IPv6 ping to 3ffe:ffff:100::1 routed through an IPv6-in-IPv4-tunnel 1.2.3.4 and 5.6.7.8 are tunnel endpoints (all addresses are examples) 5.6.7.8: 2002:ffff:f5f8::1 > 3ffe:ffff:100::1: icmp6: echo request ]]> 1.2.3.4: 3ffe:ffff:100::1 > 2002:ffff:f5f8::1: icmp6: echo reply (len ]]> 5.6.7.8: 2002:ffff:f5f8::1 > 3ffe:ffff:100::1: icmp6: echo request ]]> 1.2.3.4: 3ffe:ffff:100::1 > 2002:ffff:f5f8::1: icmp6: echo reply (len ]]> IPv6-ready programs Current distributions already contain the most needed IPv6 enabled client and servers. See first on IPv6+Linux-Status-Distribution. If still not included, you can check IPv6 & Linux - Current Status - Applications whether the program is already ported to IPv6 and usable with Linux. For common used programs there are some hints available at IPv6 & Linux - HowTo - Part 3 and IPv6 & Linux - HowTo - Part 4. IPv6-ready client programs (selection) To run the following shown tests, it's required that your system is IPv6 enabled, and some examples show addresses which only can be reached if a connection to the 6bone is available. Checking DNS for resolving IPv6 addresses Because of security updates in the last years every Domain Name System (DNS) server should run newer software which already understands the (intermediate) IPv6 address-type AAAA (the newer one named A6 isn't still common at the moment because only supported using BIND9 and newer and also the non-existent support of root domain IP6.ARPA). A simple test whether the used system can resolve IPv6 addresses is and should show something like following: IPv6-ready telnet clients IPv6-ready telnet clients are available. A simple test can be done with If the telnet client don't understand the IPv6 address and says something like "cannot resolve hostname", then it's not IPv6-enabled. IPv6-ready ssh clients openssh Current versions of openssh are IPv6-ready. Depending on configuring before compiling it has two behavior. --without-ipv4-default: the client tries an IPv6 connect first automatically and fall back to IPv4 if not working --with-ipv4-default: default connection is IPv4, IPv6 connection must be force like following example shows If your ssh client doesn't understand the option "-6" then it's not IPv6-enabled, like most ssh version 1 packages. ssh.com SSH.com's SSH client and server is also IPv6 aware now and is free for all Linux and FreeBSD machine regardless if used for personal or commercial use. IPv6-ready web browsers A current status of IPv6 enabled web browsers is available at IPv6+Linux-status-apps.html#HTTP. Most of them have unresolved problems at the moment If using an IPv4 only proxy in the settings, IPv6 requests will be sent to the proxy, but the proxy will fail to understand the request and the request fails. Solution: update proxy software (see later). Automatic proxy settings (*.pac) cannot be extended to handle IPv6 requests differently (e.g. don't use proxy) because of their nature (written in Java-script and well hard coded in source like to be seen in Maxilla source code). Also older versions don't understand an URL with IPv6 encoded addresses like http://[3ffe:400:100::1]/ (this given URL only works with an IPv6-enabled browser!). A short test is to try shown URL with a given browser and using no proxy. URLs for testing A good starting point for browsing using IPv6 is http://www.kame.net/. If the turtle on this page is animated, the connection is via IPv6, otherwise the turtle is static. IPv6-ready server programs In this part of this HOWTO, more client specific issues are mentioned. Therefore hints for IPv6-ready servers like sshd, httpd, telnetd, etc. are shown below in Hints for IPv6-enabled daemons. FAQ (IPv6-ready system check) Using tools Q: Cannot ping6 to link-local addresses Error message: "connect: Invalid argument" Kernel doesn't know, which physical or virtual link you want to use to send such ICMPv6 packets. Therefore it displays this error message. Solution: Specify interface like: "ping6 -I eth0 fe80::2e0:18ff:fe90:9205", see also program ping6 usage. Q: Cannot ping6 or traceroute6 as normal user Error message: "icmp socket: Operation not permitted" These utilities create special ICMPv6 packets and send them out. This is done by using raw sockets in the kernel. But raw sockets can only be used by the "root" user. Therefore normal users get such error message. Solution: If it's really needed that all users should be able to use these utilities, you can add the "suid" bit using "chmod u+s /path/to/program", see also program ping6 usage. If not all users should be able to, you can change the group of the program to e.g. "wheel", add these power users to this group and remove the execution bit for other users using "chmod o-rwx /path/to/program". Or configure "sudo" to enable your security policy. Configuring interfaces Different network devices On a node, there exist different network devices. They can be collected in classes Physically bounded, like eth0, tr0 Virtually existing, like ppp0, tun0, tap0, sit0, isdn0, ippp0 Physically bounded Physically bounded interfaces like Ethernet or Token-Ring are normal ones and need no special treatment. Virtually bounded Virtually bounded interfaces always need special support IPv6-in-IPv4 tunnel interfaces These interfaces are normally named sitx. The name sit is a shortcut for Simple Internet Transition. This device has the capability to encapsulate IPv6 packets into IPv4 ones and tunnel them to a foreign endpoint. sit0 has a special meaning and cannot be used for dedicated tunnels. PPP interfaces PPP interfaces get their IPv6 capability from an IPv6 enabled PPP daemon. ISDN HDLC interfaces IPv6 capability for HDLC with encapsulation ip is already built-in in the kernel ISDN PPP interfaces ISDN PPP interfaces (ippp) aren't IPv6 enabled by kernel. Also there are also no plans to do that because in kernel 2.5.+ they will be replaced by a more generic ppp interface layer. SLIP + PLIP Like mentioned earlier, this interfaces don't support IPv6 transport (sending is OK, but dispatching on receiving don't work). Ether-tap device Ether-tap devices are IPv6-enabled and also stateless configured. For use, the module "ethertap" has to be loaded before. tun devices Currently not tested by me. ATM 01/2002: Aren't currently supported by vanilla kernel, supported by USAGI extension Others Did I forget an interface?... Bringing interfaces up/down Two methods can be used to bring interfaces up or down. Using "ip" Usage: up ]]> down ]]> Example: Using "ifconfig" Usage: up ]]> down ]]> Example: Configuring IPv6 addresses There are different ways to configure an IPv6 address on an interface. You can use use "ifconfig" or "ip". Displaying existing IPv6 addresses First you should check, whether and which IPv6 addresses are already configured (perhaps auto-magically during stateless auto-configuration). Using "ip" Usage: ]]> Example for a static configured host: Example for a host which is auto-configured Here you see some auto-magically configured IPv6 addresses and their lifetime. Using "ifconfig" Usage: ]]> Example (output filtered with grep to display only IPv6 addresses). Here you see different IPv6 addresses with different scopes. Add an IPv6 address Adding an IPv6 address is similar to the mechanism of "IP ALIAS" addresses in Linux IPv4 addressed interfaces. Using "ip" Usage: / dev ]]> Example: Using "ifconfig" Usage: inet6 add / ]]> Example: Removing an IPv6 address Not so often needed, be carefully with removing non existent IPv6 address, sometimes using older kernels it results in a crash. Using "ip" Usage: / dev ]]> Example: Using "ifconfig" Usage: inet6 del / ]]> Example: Configuring normal IPv6 routes If you want to leave your link and want to send packets in the world wide IPv6-Internet, you need routing. If there is already an IPv6 enabled router on your link, it's possible enough to add IPv6 routes. Also here there are different ways to configure an IPv6 address on an interface. You can use use "ifconfig" or "ip" Displaying existing IPv6 routes First you should check, whether and which IPv6 addresses are already configured (perhaps auto-magically during auto-configuration). Using "ip" Usage: ] ]]> Example: Using "route" Usage: Example (output is filtered for interface eth0). Here you see different IPv6 routes for different addresses on a single interface. Add an IPv6 route through a gateway Mostly needed to reach the outside with IPv6 using an IPv6-enabled router on your link. Using "ip" Usage: / via ]]>] ]]> Example: Using "route" Usage: / gw ]]> [dev ] ]]> A device can be needed, too, if the IPv6 address of the gateway is a link local one. Following shown example adds a route for all currently global addresses (2000::/3) through gateway 3ffe:ffff:0:f101::1 Removing an IPv6 route through a gateway Not so often needed manually, mostly done by network configure scripts on shutdown (full or per interface) Using "ip" Usage: / via ]]>] ]]> Example: Using "route" Usage: / [dev ] ]]> Example for removing upper added route again: Add an IPv6 route through an interface Not often needed, sometimes in cases of dedicated point-to-point links. Using "ip" Usage: / dev ]]> Example: Metric "1" is used here to be compatible with the metric used by route, because the default metric on using "ip" is "1024". Using "route" Usage: / dev ]]> Example: Removing an IPv6 route through an interface Not so often needed to use by hand, configuration scripts will use such on shutdown. Using "ip" Usage: / dev ]]> Example: Using "route" Usage: / dev ]]> Example: FAQ for IPv6 routes Support of an IPv6 default route One idea of IPv6 was a hierachical routing, therefore only less routing entries are needed in routers. There are some issues in current Linux kernels: Clients (not routing any packet!) Client can setup a default route like prefix "::/0", they also learn such route on autoconfiguration e.g. using radvd on the link like following example shows: Routers in case of packet forwarding Current mainstream Linux kernel (at least <= 2.4.17) don't support default routes. You can set them up, but the route lookup fails when a packet should be forwarded (normal intention of a router). Therefore at this time "default routing" can be setup using the currently only global address prefix "2000::/3". The USAGI project already supports this in their extension with a hack. Note: take care about default routing without address filtering on edge routers. Otherwise unwanted multicast or site-local traffic leave the edge. Neighbor Discovery Neighbor discovery was the IPv6 successor for the ARP (Address Resolution Protocol) in IPv4. You can retrieve information about the current neighbors, in addition you can set and delete entries. The kernel keeps tracking of successful neighbor detection (like ARP in IPv4). You can dig into the learnt table using "ip". Displaying neighbors using "ip" With following command you can display the learnt or configured IPv6 neighbors ] ]]> The following example shows one neighbor, which is a reachable router Manipulating neighbors table using "ip" Manually add an entry With following command you are able to manually add an entry lladdr dev ]]> Example: Manually delete an entry Like adding also an entry can be deleted: lladdr dev ]]> Example: More advanced settings The tool "ip" is less documentated, but very strong. See online "help" for more: Looks like some options are only for IPv4...if you can contribute information about flags and advanced usage, pls. send. Configuring IPv6-in-IPv4 tunnels If you want to leave your link you have no IPv6 capable network around you, you need IPv6-in-IPv4 tunneling to reach the world wide IPv6-Internet. There are some kind of tunnel mechanism and also some possibilities to setup tunnels. Types of tunnels There are more than one possibility to tunnel IPv6 packets over IPv4-only links. Static point-to-point tunneling: 6bone A point-to-point tunnel is a dedicated tunnel to an endpoint, which knows about your IPv6 network (for backward routing) and the IPv4 address of your tunnel endpoint and defined in RFC 2893 / Transition Mechanisms for IPv6 Hosts and Routers. Requirements: IPv4 address of your local tunnel endpoint must be static, global unique and reachable from the foreign tunnel endpoint A global IPv6 prefix assigned to you (see 6bone registry) A foreign tunnel endpoint which is capable to route your IPv6 prefix to your local tunnel endpoint (mostly remote manual configuration required) Automatically tunneling Automatic tunneling occurs, when a node directly connects another node gotten the IPv4 address of the other node before. 6to4-Tunneling 6to4 tunneling (RFC 3056 / Connection of IPv6 Domains via IPv4 Clouds) uses a simple mechanism to create automatic tunnels. Each node with a global unique IPv4 address is able to be a 6to4 tunnel endpoint (if no IPv4 firewall prohibits traffic). 6to4 tunneling is mostly not a one-to-one tunnel. This case of tunneling can be divided into upstream and downstream tunneling. Also, a special IPv6 address indicates that this node will use 6to4 tunneling for connecting the world-wide IPv6 network Generation of 6to4 prefix The 6to4 address is defined like following (schema is taken from RFC 3056 / Connection of IPv6 Domains via IPv4 Clouds): FP and TLA together (16 bits) have the value 0x2002. V4ADDR is the node's global unique IPv4 address (in hexadecimal notation). SLA is the subnet identifier (65536 local subnets possible) and are usable to represent your local network structure. For gateways, such prefix is generated by normally using SLA "0000" and suffix "::1" and assigned to the 6to4 tunnel interface. 6to4 upstream tunneling The node has to know to which foreign tunnel endpoint its in IPv4 packed IPv6 packets should be send to. In "early" days of 6to4 tunneling, dedicated upstream accepting routers were defined. See NSayer's 6to4 information for a list of routers. Nowadays, 6to4 upstream routers can be found auto-magically using the anycast address 192.88.99.1. In the background routing protocols handle this, see RFC 3068 / An Anycast Prefix for 6to4 Relay Routers for details. 6to4 downstream tunneling The downstream (6bone -> your 6to4 enabled node) is not really fix and can vary from foreign host which originated packets were send to. There exist two possibilities: Foreign host uses 6to4 and sends packet direct back to your node (see below) Foreign host sends packets back to the world-wide IPv6 network and depending on the dynamic routing a relay router create a automatic tunnel back to your node. Possible 6to4 traffic from 6to4 to 6to4: is normally directly tunneled between the both 6to4 enabled hosts from 6to4 to non-6to4: is sent via upstream tunneling non-6to4 to 6to4: is sent via downstream tunneling Displaying existing tunnels Using "ip" Usage: ] ]]> Example: Using "route" Usage: Example (output is filtered to display only tunnels through virtual interface sit0): Setup of point-to-point tunnel There are 3 possibilities to add or remove point-to-point tunnels. A good additional information about tunnel setup using "ip" is Configuring tunnels with iproute2 (article) (Mirror). Add point-to-point tunnels Using "ip" Common method at the moment for a small amount of tunnels. Usage for creating a tunnel device (but it's not up afterward, also a TTL must be specified because the default value is 0). mode sit ttl remote ]]> local ]]> Usage (generic example for three tunnels): remote ]]> local ]]> dev sit1 metric 1 ]]> ]]> local ]]> dev sit2 metric 1 ]]> ]]> local ]]> dev sit3 metric 1 ]]> Using "ifconfig" and "route" (deprecated) This not very recommended way to add a tunnel because it's a little bit strange. No problem if adding only one, but if you setup more than one, you cannot easy shutdown the first ones and leave the others running. Usage (generic example for three tunnels): ]]> dev sit1 ]]> ]]> dev sit2 ]]> ]]> dev sit3 ]]> Important: DON'T USE THIS, because this setup implicit enable "automatic tunneling" from anywhere in the Internet, this is a risk, and it should not be advocated. Using "route" only It's also possible to setup tunnels in Non Broadcast Multiple Access (NBMA) style, it's a easy way to add many tunnels at once. But none of the tunnel can be numbered (which is a not required feature). Usage (generic example for three tunnels): gw ]]> dev sit0 ]]> gw ]]> dev sit0 ]]> gw ]]> dev sit0 ]]> Important: DON'T USE THIS, because this setup implicit enable "automatic tunneling" from anywhere in the Internet, this is a risk, and it should not be advocated. Removing point-to-point tunnels Manually not so often needed, but used by scripts for clean shutdown or restart of IPv6 configuration. Using "ip" Usage for removing a tunnel device: ]]> Usage (generic example for three tunnels): dev sit1 ]]> dev sit2 ]]> dev sit3 ]]> Using "ifconfig" and "route" (deprecated because not very funny) Not only the creation is strange, the shutdown also...you have to remove the tunnels in backorder, means the latest created must be removed first. Usage (generic example for three tunnels): dev sit3 ]]> dev sit2 ]]> dev sit1 ]]> Using "route" This is like removing normal IPv6 routes. Usage (generic example for three tunnels): gw ]]> dev sit0 ]]> gw ]]> dev sit0 ]]> gw ]]> dev sit0 ]]> Numbered point-to-point tunnels Sometimes it's needed to configure a point-to-point tunnel with IPv6 addresses like in IPv4 today. This is only possible with the first (ifconfig+route - deprecated) and third (ip+route) tunnel setup. In such cases, you can add the IPv6 address to the tunnel interface like shown on interface configuration. Setup of 6to4 tunnels Pay attention that the support of 6to4 tunnels currently lacks on vanilla kernel series 2.2.x (see systemcheck/kernel for more information). Also note that that the prefix length for a 6to4 address is 16 because of from network point of view, all other 6to4 enabled hosts are on the same layer 2. Add a 6to4 tunnel First, you have to calculate your 6to4 prefix using your local assigned global routable IPv4 address (if your host has no global routable IPv4 address, in special cases NAT on border gateways is possible): Assuming your IPv4 address is the generated 6to4 prefix will be Local 6to4 gateways should always assigned the suffix "::1", therefore your local 6to4 address will be Use e.g. following for automatic generation: There are two ways possible to setup 6to4 tunneling now. Using "ip" and a dedicated tunnel device This is now the recommended way (a TTL must be specified because the default value is 0). Create a new tunnel device remote any local ]]> Bring interface up Add local 6to4 address to interface (note: prefix length 16 is important!) /16 dev tun6to4 ]]> Add (default) route to the global IPv6 network using the all-6to4-routers IPv4 anycast address Using "ifconfig" and "route" and generic tunnel device "sit0" (deprecated) This is now deprecated because using the generic tunnel device sit0 doesn't let specify filtering per device. Bring generic tunnel interface sit0 up Add local 6to4 address to interface /16 ]]> Add (default) route to the global IPv6 network using the all-6to4-relays IPv4 anycast address Remove a 6to4 tunnel Using "ip" and a dedicated tunnel device Remove all routes through this dedicated tunnel device Shut down interface Remove created tunnel device Using "ifconfig" and "route" and generic tunnel device "sit0" (deprecated) Remove (default) route through the 6to4 tunnel interface Remove local 6to4 address to interface /16 ]]> Shut down generic tunnel device (take care about this, perhaps it's still in use...) Configuring IPv4-in-IPv6 tunnels This will be filled in the future. At the moment, such tunnels are more used in test environments. More information in the meantime: RFC 2473 / Generic Packet Tunneling in IPv6 Specification Kernel settings in /proc-filesystem Note: the source of this section is mostly the file "ip-sysctl.txt" which is included in current kernel sources in directory "Documentation/networking". Credits to Pekka Savola for maintaining the IPv6-related part in this file. Also some text is more or less copied & pasted into this document. How to access the /proc-filesystem Using "cat" and "echo" Using "cat" and "echo" is the simplest way to access the /proc filesystem, but some requirements are needed for that The /proc-filesystem had to be enabled in kernel, means on compiling following switch has to be set The /proc-filesystem was mounted before, which can be tested using You need read and sometimes also write access (normally root only) to the /proc-filesystem Normally, only entries in /proc/sys/* are writable, the others are readonly and for information retrieving only. Retrieving a value The value of an entry can be retrieved using "cat": Setting a value A new value can be set (if entry is writable) using "echo": /proc/sys/net/ipv6/conf/all/forwarding ]]> Using "sysctl" Using the "sysctl" program to access the kernel switches is a modern method today. You can use it also, if the /proc-filesystem isn't mounted. But you have only access to /proc/sys/*! The program "sysctl" is included in package "procps" (on Red Hat Linux systems). The sysctl-interface had to be enabled in kernel, means on compiling following switch has to be set Retrieving a value The value of an entry can be retrieved now: Setting a value A new value can be set (if entry is writable): Note: Don't use spaces around the "=" on setting values. Also on multiple values per line, quote them like e.g. Additionals Note: There are sysctl versions in the wild which displaying "/" instead of the "." For more details take a look into sysctl's manpage. Hint: for digging fast into the settings, use the option "-a" (display all entries) in conjunction with "grep". Values found in /proc-filesystems There are several formats seen in /proc-filesystem: BOOLEAN: simple a "0" (false) or a "1" (true) INTEGER: an integer value, can be unsigned, too more sophisticated lines with several values: sometimes a header line is displayed also, if not, have a look into the kernel source to retrieve information about the meaning of each value... Entries in /proc/sys/net/ipv6/ conf/default/* Change the interface-specific default settings. conf/all/* Change all the interface-specific settings. Exception: "conf/all/forwarding" has a different meaning here conf/all/forwarding Type: BOOLEAN This enables global IPv6 forwarding between all interfaces. In IPv6 you can't control forwarding per device, forwarding control has to be done using IPv6-netfilter (controlled with ip6tables) rulesets and specify input and output devices (see Firewalling/Netfilter6 for more). This is different to IPv4, where you are able to control forwarding per device (decision is made on interface where packet came in). This also sets all interfaces' Host/Router setting 'forwarding' to the specified value. See below for details. This referred to as global forwarding. If this value is 0, no IPv6 forwarding is enabled, packets never leave another interface, neither physical nor logical like e.g. tunnels. conf/interface/* Change special settings per interface. The functional behaviour for certain settings is different depending on whether local forwarding is enabled or not. accept_ra Type: BOOLEAN Functional default: enabled if local forwarding is disabled. disabled if local forwarding is enabled. Accept Router Advertisements, and autoconfigure this interface with received data. accept_redirectsc Type: BOOLEAN Functional default: enabled if local forwarding is disabled. disabled if local forwarding is enabled. Accept Redirects sent by an IPv6 router. autoconf Type: BOOLEAN Default: TRUE Configure link-local addresses (see also Addresstypes) using L2 hardware addresses. E.g. this generates automagically an address like "fe80::201:23ff:fe45:6789" on an interface with a L2-MAC address. dad_transmits Type: INTEGER Default: 1 The amount of Duplicate Address Detection probes to send. forwarding Type: BOOLEAN Default: FALSE if global forwarding is disabled (default), otherwise TRUE Configure interface-specific Host/Router behaviour. Note: It is recommended to have the same setting on all interfaces; mixed router/host scenarios are rather uncommon. Value FALSE: By default, Host behaviour is assumed. This means: IsRouter flag is not set in Neighbour Advertisements. Router Solicitations are being sent when necessary. If accept_ra is TRUE (default), accept Router Advertisements (and do autoconfiguration). If accept_redirects is TRUE (default), accept Redirects. Value TRUE: If local forwarding is enabled, Router behaviour is assumed. This means exactly the reverse from the above: IsRouter flag is set in Neighbour Advertisements. Router Solicitations are not sent. Router Advertisements are ignored. Redirects are ignored. hop_limit Type: INTEGER Default: 64 Default Hop Limit to set. mtu Type: INTEGER Default: 1280 (IPv6 required minimum) Default Maximum Transfer Unit router_solicitation_delay Type: INTEGER Default: 1 Number of seconds to wait after interface is brought up before sending Router Solicitations. router_solicitation_interval Type: INTEGER Default: 4 Number of seconds to wait between Router Solicitations. router_solicitations Type: INTEGER Default: 3 Number of Router Solicitations to send until assuming no routers are present. neigh/default/* Change default settings for neighbor detection and some special global interval and threshold values: gc_thresh1 Type: INTEGER Default: 128 More to be filled. gc_thresh2 Type: INTEGER Default: 512 More to be filled. gc_thresh3 Type: INTEGER Default: 1024 Tuning parameter for neighbour table size. Increase this value if you have a lot of interfaces and problem with routes start to act mysteriously and fail. Or if a running Zebra (routing daemon) reports: gc_interval Type: INTEGER Default: 30 More to be filled. neigh/interface/* Change special settings per interface for neighbor detection. anycast_delay Type: INTEGER Default: 100 More to be filled. gc_stale_time Type: INTEGER Default: 60 More to be filled. proxy_qlen Type: INTEGER Default: 64 More to be filled. unres_qlen Type: INTEGER Default: 3 More to be filled. app_solicit Type: INTEGER Default: 0 More to be filled. locktime Type: INTEGER Default: 0 More to be filled. retrans_time Type: INTEGER Default: 100 More to be filled. base_reachable_time Type: INTEGER Default: 30 More to be filled. mcast_solicit Type: INTEGER Default: 3 More to be filled. ucast_solicit Type: INTEGER Default: 3 More to be filled delay_first_probe_time Type: INTEGER Default: 5 More to be filled. proxy_delay Type: INTEGER Default: 80 More to be filled. route/* Change global settings for routing. flush Removed in newer kernel releases - more to be filled. gc_interval Type: INTEGER Default: 30 More to be filled. gc_thresh Type: INTEGER Default: 1024 More to be filled. mtu_expires Type: INTEGER Default: 600 More to be filled. gc_elasticity Type: INTEGER Default: 0 More to be filled. gc_min_interval Type: INTEGER Default: 5 More to be filled. gc_timeout Type: INTEGER Default: 60 More to be filled. min_adv_mss Type: INTEGER Default: 12 More to be filled. max_size Type: INTEGER Default: 4096 More to be filled. IPv6-related entries in /proc/sys/net/ipv4/ At the moment (and this will be until IPv4 is completly converted to an independend kernel module) some switches are also used here for IPv6. ip_* ip_local_port_range This control setting is used by IPv6 also. tcp_* This control settings are used by IPv6 also. icmp_* This control settings are not used by IPv6. To enable ICMPv6 rate limiting (which is very recommended because of the capability of ICMPv6 storms) netfilter-v6 rules must be used. others Unknown, but probably not used by IPv6. IPv6-related entries in /proc/net/ In /proc/net there are several read-only entries available. You cannot retrieve information using "sysctl" here, so use e.g. "cat". if_inet6 Type: One line per addresss containing multiple values Here all configured IPv6 addresses are shown in a special format. The example displays for loopback interface only. The meaning is shown below (see "net/ipv6/addrconf.c" for more). IPv6 address displayed in 32 hexadecimal chars without colons as separator Netlink device number (interface index) in hexadecimal (see "ip addr" , too) Prefix length in hexadecimal Scope value (see kernel source " include/net/ipv6.h" and "net/ipv6/addrconf.c" for more) Interface flags (see "include/linux/rtnetlink.h" and "net/ipv6/addrconf.c" for more) Device name ipv6_route Type: One line per route containing multiple values Here all configured IPv6 routes are shown in a special format. The example displays for loopback interface only. The meaning is shown below (see "net/ipv6/route.c" for more). IPv6 destination network displayed in 32 hexadecimal chars without colons as separator IPv6 destination prefix length in hexadecimal IPv6 source network displayed in 32 hexadecimal chars without colons as separator IPv6 source prefix length in hexadecimal IPv6 next hop displayed in 32 hexadecimal chars without colons as separator Metric in hexadecimal Reference counter Use counter Flags Device name sockstat6 Type: One line per protocol with description and value Statistics about used IPv6 sockets. Example: tcp6 To be filled. udp6 To be filled. igmp6 To be filled. raw6 To be filled. ip6_flowlabel To be filled. rt6_stats To be filled. snmp6 Type: One line per SNMP description and value SNMP statistics, can be retrieved via SNMP server and related MIB table by network management software. ip6_tables_names Available netfilter6 tables Netlink-Interface to kernel To be filled...I have no experience with that... Network debugging Server socket binding Using "netstat" for server socket binding check It's always interesting which server sockets are currently active on a node. Using "netstat" is a short way to get such information: Used options: -nlptu Example: Examples for tcpdump packet dumps Here some examples of captured packets are shown, perhaps useful for your own debugging... ...more coming next... Router discovery Router advertisement ff02::1: icmp6: router ]]> Router with link-local address "fe80::212:34ff:fe12:3450" send an advertisement to the all-node-on-link multicast address "ff02::1" containing two prefixes "2002:0102:0304:1::/64" (lifetime 30 s) and "3ffe:ffff:0:1::/64" (lifetime 2592000 s) including its own layer 2 MAC address "0:12:34:12:34:50". Router solicitation ff02::2: icmp6: router solicitation ]]> Node with link-local address "fe80::212:34ff:fe12:3456" and layer 2 MAC address "0:12:34:12:34:56" is looking for a router on-link, therefore sending this solicitation to the all-router-on-link multicast address "ff02::2". Neighbor discovery Neighbor discovery solicitation for duplicate address detection Following packets are sent by a node with layer 2 MAC address "0:12:34:12:34:56" during autoconfiguration to check whether a potential address is already used by another node on the link sending this to the solicited-node link-local multicast address. Node wants to configure its link-local address "fe80::212:34ff:fe12:3456", checks for duplicate now ff02::1:ff12:3456: icmp6: neighbor sol: who has ]]> Node wants to configure its global address "2002:0102:0304:1:212:34ff:fe12:3456" (after receiving advertisement shown above), checks for duplicate now ff02::1:ff12:3456: icmp6: neighbor sol: who has ]]> Node wants to configure its global address "3ffe:ffff:0:1:212:34ff:fe12:3456" (after receiving advertisement shown above), checks for duplicate now ff02::1:ff12:3456: icmp6: neighbor sol: who has ]]> Neighbor discovery solicitation for looking for host or gateway Node wants to send packages to "3ffe:ffff:0:1::10" but has no layer 2 MAC address to send packet, so send solicitation now ff02::1:ff00:10: icmp6: ]]> Node looks for "fe80::10" now ff02::1:ff00:10: icmp6: neighbor ]]> Support for persistent IPv6 configuration in Linux distributions Some Linux distribution contain already support of a persistent IPv6 configuration using existing or new configuration and script files and some hook in the IPv4 script files. Red Hat Linux and "clones" Since starting writing the IPv6 & Linux - HowTo it was my intention to enable a persistent IPv6 configuration which catch most of the wished cases like host-only, router-only, dual-homed-host, router with second stub network, normal tunnels, 6to4 tunnels, and so on. Nowadays there exists a set of configuration and script files which do the job very well (never heard about real problems, but I don't know how many use the set). Because this configuration and script files are extended from time to time, they got their own homepage: initscripts-ipv6 homepage (Mirror). Because I began my IPv6 experience using a Red Hat Linux 5.0 clone, my IPv6 development systems are mostly Red Hat Linux based now, it's kind a logic that the scripts are developed for this kind of distribution (so called historic issue). Also it was very easy to extend some configuration files, create new ones and create some simple hook for calling IPv6 setup during IPv4 setup. Fortunately, in Red Hat Linux since 7.1 a snapshot of my IPv6 scripts is included, this was and is still further on assisted by Pekka Savola. Mandrake since version 8.0 also includes an IPv6-enabled initscript package, but a minor bug still prevents usage ("ifconfig" misses "inet6" before "add"). Test for IPv6 support of network configuration scripts You can test, whether your Linux distribution contain support for persistent IPv6 configuration using my set. Following script library should exist: Auto-magically test: The version of the library is important if you miss some features. You can get it executing following (or easier look at the top of the file): In shown example, the used version is 20011124. Check this against latest information on initscripts-ipv6 homepage (Mirror) to see what has been changed. You will find there also a change-log. Short hint for enabling IPv6 on current RHL 7.1, 7.2, 7.3, ... Check whether running system has already IPv6 module loaded If result is "off", then enable IPv6 networking by editing /etc/sysconfig/network, add following new line Reboot or restart networking using Now IPv6 module should be loaded If your system is on a link which provides router advertisement, autoconfiguration will be done automatically. For more information which settings are supported see /usr/share/doc/initscripts-$version/sysconfig.txt. SuSE Linux In newer 7.x versions there is a really rudimentary support available, see /etc/rc.config for details. Because of the really different configuration and script file structure it is hard (or impossible) to use the set for Red Hat Linux and clones with this distribution. In versions 8.x they completly change their configuration setup. SuSE Linux 7.3 How to setup 6to4 IPv6 with SuSE 7.3 SuSE Linux 8.0 IPv6 address configuration Edit file /etc/sysconfig/network/ifcfg-<Interface-Name> and setup following value /" ]]> Additional information See file /usr/share/doc/packages/sysconfig/README SuSE Linux 8.1 IPv6 address configuration Edit file /etc/sysconfig/network/ifcfg-<Interface-Name> and setup following value /" ]]> Additional information See file /usr/share/doc/packages/sysconfig/Network Debian Linux Following information was contributed by Stephane Bortzmeyer <bortzmeyer at nic dot fr> Be sure that IPv6 is loaded, either because it is compiled into the kernel or because the module is loaded. For the latest, three solutions, adding it to /etc/modules, using the pre-up trick shown later or using kmod (not detailed here). Configure your interface. Here we assume eth0 and address (3ffe:ffff:1234:5::1:1). Edit /etc/network/interfaces: /proc/sys/net/ipv6/conf/all/autoconf ]]> And you reboot or you just and you have your static address. Further information IPv6 on Debian Linux by Craig Small Jean-Marc V. Liotier's HOWTO for Freenet6 & Debian Users (announced 24.12.2002 on mailinglist users@ipv6.org ) Auto-configuration and mobility Stateless auto-configuration Is supported and seen on the assigned link-local address after an IPv6-enabled interface is up. Stateful auto-configuration using Router Advertisement Daemon (radvd) to be filled. See radvd daemon autoconfiguration below. Dynamic Host Configuration Protocol v6 (DHCPv6) to be filled. For the moment, see Issues Concerning DHCP in IPv6 Specifications; Dynamic Host Configuration Protocol for IPv6 (DHCPv6) ; A Guide to Implementing Stateless DHCPv6 Service and DHCPv6 Options for SIP Servers for more details. Mobility to be filled. For the moment, see Mobile IPv6 for Linux(MIPL) homepage for more details. Further infos can be found here: MIPv6 Care of Address Option Mobile IPv6 Fast Handovers for 802.11 Networks IPv6 Anycast Binding using Return Routability Localized Key Management for AAA in MobileIPv6 Taxonomy of Route Optimization Models in the NEMO Context Diameter Mobile IPv6 Application Global Connectivity for IPv6 Mobile Ad Hoc Networks Fast Handovers for Mobile IPv6 Mobility Support in IPv6 Mobile IPv6 VPN using Gateway Home Agent Hierarchical MIPv6 mobility management (HMIPv6) IPv6 Fast Router Advertisement Securing MIPv6 Binding Updates Using Address Based Keys (ABKs) Mobile IPv6 Issue List Hop-by-Hop Local Mobility Agents Probing for Mobile IPv6 IPv6 Reverse Routing Header and its application to Mobile Networks Using IPsec to Protect Mobile IPv6 Signaling between Mobile Nodes and Home Agents Regional Mobile IPv6 mobility management IPv6 over Mobile IPv4 Improving the Architectural Alignment for FMIPv6 Mobile IPv6 Authentication, Authorization, and Accounting Requirements RObust Header Compression (ROHC): A Compression Profile for Mobile IPv6 Firewalling IPv6 firewalling is important, especially if using IPv6 on internal networks with global IPv6 addresses. Because unlike at IPv4 networks where in common internal hosts are protected automatically using private IPv4 addresses like RFC 1918 / Address Allocation for Private Internets or Automatic Private IP Addressing (APIPA)Google search for Microsoft + APIPA, in IPv6 normally global addresses are used and someone with IPv6 connectivity can reach all internal IPv6 enabled nodes. Firewalling using netfilter6 Native IPv6 firewalling is only supported in kernel versions 2.4+. In older 2.2- you can only filter IPv6-in-IPv4 by protocol 41. Attention: no warranty that described rules or examples can really protect your system! Audit your ruleset after installation, see for more. More information Netfilter project maillist archive of netfilter users maillist archive of netfilter developers Unofficial status informations Preparation Get sources Get the latest kernel source: http://www.kernel.org/ Get the latest iptables package: Source tarball (for kernel patches): http://www.netfilter.org/ Source RPM for rebuild of binary (for RedHat systems): ftp://ftp.redhat.com/redhat/linux/rawhide/SRPMS/SRPMS/ or perhaps also at http://www.netcore.fi/pekkas/linux/ipv6/ Extract sources Change to source directory: Unpack and rename kernel sources Unpack iptables sources Apply latest iptables/IPv6-related patches to kernel source Change to iptables directory Apply pending patches Apply additional IPv6 related patches (still not in the vanilla kernel included) Say yes at following options (iptables-1.2.2) ah-esp.patch masq-dynaddr.patch (only needed for systems with dynamic IP assigned WAN connections like PPP or PPPoE) ipv6-agr.patch.ipv6 ipv6-ports.patch.ipv6 LOG.patch.ipv6 REJECT.patch.ipv6 Check IPv6 extensions Configure, build and install new kernel Change to kernel sources Edit Makefile Run configure, enable IPv6 related Configure other related to your system, too Compilation and installing: see the kernel section here and other HOWTOs Rebuild and install binaries of iptables Make sure, that upper kernel source tree is also available at /usr/src/linux/ Rename older directory Create a new softlink Rebuild SRPMS Install new iptables packages (iptables + iptables-ipv6) On RH 7.1 systems, normally, already an older version is installed, therefore use "freshen" If not already installed, use "install" On RH 6.2 systems, normally, no kernel 2.4.x is installed, therefore the requirements don't fit. Use "--nodeps" to install it Perhaps it's necessary to create a softlink for iptables libraries where iptables looks for them Usage Check for support Load module, if so compiled Check for capability Learn how to use ip6tables List all IPv6 netfilter entries Short Extended List specified filter Insert a log rule at the input filter with options Insert a drop rule at the input filter Delete a rule by number Allow ICMPv6 Using older kernels (unpatched kernel 2.4.5 and iptables-1.2.2) no type can be specified Accept incoming ICMPv6 through tunnels Allow outgoing ICMPv6 through tunnels Newer kernels allow specifying of ICMPv6 types: Rate-limiting Because it can happen (author already saw it to times) that an ICMPv6 storm will raise up, you should use available rate limiting for at least ICMPv6 ruleset. In addition logging rules should also get rate limiting to prevent DoS attacks against syslog and storage of log file partition. An example for a rate limited ICMPv6 looks like: Allow incoming SSH Here an example is shown for a ruleset which allows incoming SSH connection from a specified IPv6 address Allow incoming SSH from 3ffe:ffff:100::1/128 Allow response packets (at the moment IPv6 connection tracking isn't in mainstream netfilter6 implemented) Enable tunneled IPv6-in-IPv4 To accept tunneled IPv6-in-IPv4 packets, you have to insert rules in your IPv4 firewall setup relating to such packets, for example Accept incoming IPv6-in-IPv4 on interface ppp0 Allow outgoing IPv6-in-IPv4 to interface ppp0 If you have only a static tunnel, you can specify the IPv4 addresses, too, like Accept incoming IPv6-in-IPv4 on interface ppp0 from tunnel endpoint 1.2.3.4 Allow outgoing IPv6-in-IPv4 to interface ppp0 to tunnel endpoint 1.2.3.4 Protection against incoming TCP connection requests VERY RECOMMENDED! For security issues you should really insert a rule which blocks incoming TCP connection requests. Adapt "-i" option, if other interface names are in use! Block incoming TCP connection requests to this host Block incoming TCP connection requests to hosts behind this router Perhaps the rules have to be placed below others, but that is work you have to think about it. Best way is to create a script and execute rules in a specified way. Protection against incoming UDP connection requests ALSO RECOMMENDED! Like mentioned on my firewall information it's possible to control the ports on outgoing UDP/TCP sessions. So if all of your local IPv6 systems are using local ports e.g. from 32768 to 60999 you are able to filter UDP connections also (until connection tracking works) like: Block incoming UDP packets which cannot be responses of outgoing requests of this host Block incoming UDP packets which cannot be responses of forwarded requests of hosts behind this router Demonstration example Following lines show a more sophisticated setup as an example. Happy netfilter6 ruleset creation.... Security Node security It's very recommended to apply all available patches and disable all not necessary services. Also bind services to the needed IPv4/IPv6 addresses only and install local firewalling. More to be filled... Access limitations Many services uses the tcp_wrapper library for access control. Below is described the use of tcp_wrapper. More to be filled... IPv6 security auditing Currently there are no comfortable tools out which are able to check a system over network for IPv6 security issues. Neither Nessus nor any commercial security scanner is as far as I know able to scan IPv6 addresses. Legal issues ATTENTION: always take care that you only scan your own systems or after receiving a written order, otherwise legal issues are able to come up to you. CHECK destination IPv6 addresses TWICE before starting a scan. Security auditing using IPv6-enabled netcat With the IPv6-enabled netcat (see IPv6+Linux-status-apps/security-auditing for more) you can run a portscan by wrapping a script around which run through a port range, grab banners and so on. Usage example: Security auditing using IPv6-enabled nmap NMap, one of the best portscaner around the world, supports IPv6 since version 3.10ALPHA1. Usage example: Security auditing using IPv6-enabled strobe Strobe is a (compared to NMap) more a low budget portscanner, but there is an IPv6-enabling patch available (see IPv6+Linux-status-apps/security-auditing for more). Usage example: . ]]> Note: strobe isn't really developed further on, the shown version number isn't the right one. Audit results If the result of an audit mismatch your IPv6 security policy, use IPv6 firewalling to close the holes, e.g. using netfilter6 (see Firewalling/Netfilter6 for more). Info: More detailed information concerning IPv6 Security can be found here: Firewalling Considerations for IPv6 / draft-savola-v6ops-firewalling-??.txt IPv6 Neighbour Discovery trust models and threats / draft-ietf-send-psreq-??.txt Security Considerations for 6to4 / draft-savola-v6ops-6to4-security-??.txt Access Control Prefix Router Advertisement Option for IPv6 / draft-bellovin-ipv6-accessprefix-??.txt Requirements for Plug and Play IPsec for IPv6 applications /draft-kobayakawa-ipsec-ipv6-pnpipsec-reqts-??.txt Security of IPv6 Routing Header and Home Address Options / draft-savola-ipv6-rh-ha-security-??.txt Encryption and Authentication Unlike in IPv4 encryption and authentication is a mandatory feature of IPv6. This features are normally implemented using IPsec (which can be also used by IPv4). But because of the independence of encryption and authentication from the key exchange protocol there exists currently some interoperability problems regarding this issue. Support in kernel Support in vanilla Linux kernel 2.4.x Currently missing in vanilla 2.4. There is an issue about keeping the Linux kernel source free of export/import-control-laws regarding encryption code. This is also one case why FreeS/WAN project (IPv4 only IPsec) isn't still contained in vanilla source. Support in USAGI kernel The USAGI project has taken over in July 2001 the IPv6 enabled FreeS/WAN code from the IABG / IPv6 Project and included in their kernel extensions. Nowadays they are working on implementing IPsec into 2.5.x series. Support in vanilla Linux kernel 2.5.x Currently, the IPsec extensions of the USAGI kernel are on the way being migrated into 2.5.x developer kernels. Usage In difference to FreeS/WAN, in IPsec of 2.5.x the IKE daemon "racoon" (taken from KAME) is used instead of "pluto" of FreeS/WAN. It has a different configuration syntax than "pluto", note also that the IPsec setup is splitted into 2 parts (IKE and topology setup). Until some documentation is filled here, take a look at Linux Advanced Routing & Traffic Control HOWTO / IPSEC. Quality of Service (QoS) IPv6 supports QoS with use of Flow Labels and Traffic Classes. This can be controlled using "tc" (contained in package "iproute"). Additional infos: IPv6 Flow Label Specification more to be filled... Hints for IPv6-enabled daemons Here some hints are shown for IPv6-enabled daemons. Berkeley Internet Name Daemon BIND (named) IPv6 is supported since version 9. Always use newest available version. At least version 9.1.3 must be used, older versions can contain remote exploitable security holes. Listening on IPv6 addresses Note: unlike in IPv4 current versions doesn't allow to bind a server socket to dedicated IPv6 addresses, so only any or none are valid. Because this can be a security issue, check the Access Control List (ACL) section below, too! Enable BIND named for listening on IPv6 address To enable IPv6 for listening, following options are requested to change This should result after restart in e.g. And a simple test looks like and should show you a result. Disable BIND named for listening on IPv6 address To disable IPv6 for listening, following options are requested to change IPv6 enabled Access Control Lists (ACL) IPv6 enabled ACLs are possible and should be used whenever it's possible. An example looks like following: This ACLs can be used e.g. for queries of clients and transfer zones to secondary name-servers. This prevents also your caching name-server to be used from outside using IPv6. It's also possible to set the allow-query and allow-transfer option for most of single zone definitions, too. Sending queries with dedicated IPv6 address This option is not required, but perhaps needed: port ; ]]> Per zone defined dedicated IPv6 addresses It's also possible to define per zone some IPv6 addresses. Transfer source address Transfer source address is used for outgoing zone transfers: [port port]; ]]> Notify source address Notify source address is used for outgoing notify messages: [port port]; ]]> IPv6 DNS zone files examples Some information can be also found at IPv6 DNS Setup Information (article). Perhaps also helpful is the IPv6 Reverse DNS zone builder for BIND 8/9 (webtool). Serving IPv6 related DNS data For IPv6 new types and root zones for reverse lookups are defined: AAAA and reverse IP6.INT: specified in RFC 1886 / DNS Extensions to support IP version 6, usable since BIND version 4.9.6 A6, DNAME (DEPRECATED NOW!) and reverse IP6.ARPA: specified in RFC 2874 / DNS Extensions to Support IPv6 Address Aggregation and Renumbering, usable since BIND 9, but see also an information about the current state at draft-ietf-dnsext-ipv6-addresses-00.txt Perhaps filled later more content, for the meantime take a look at given RFCs and AAAA and reverse IP6.INT: IPv6 DNS Setup Information A6, DNAME (DEPRECATED NOW!) and reverse IP6.ARPA: take a look into chapter 4 and 6 of the BIND 9 Administrator Reference Manual (ARM) distributed which the bind-package or get this here: BIND version 9 ARM (PDF) Because IP6.INT is deprecated (but still in use), a DNS server which will support IPv6 information has to serve both reverse zones. Current best practice Because there are some troubles around using the new formats, current best practice is: Forward lookup support: AAAA Reverse lookup support: Reverse nibble format for zone ip6.int (FOR BACKWARD COMPATIBILITY) Reverse nibble format for zone ip6.arpa (RECOMMENDED) Checking IPv6-enabled connect To check, whether BIND is listening on an IPv6 socket and serving data see following examples. IPv6 connect, but denied by ACL Specifying a dedicated server for the query, an IPv6 connect can be forced: Related log entry looks like following: If you see such entries in the log, check whether requests from this client should be allowed and perhaps review your ACL configuration. Successful IPv6 connect A successful IPv6 connect looks like following: Internet super daemon (xinetd) IPv6 is supported since xinetd version around 1.8.9. Always use newest available version. At least version 2.3.3 must be used, older versions can contain remote exploitable security holes. Some Linux distribution contain an extra package for the IPv6 enabled xinetd, some others start the IPv6-enabled xinetd if following variable is set: NETWORKING_IPV6="yes", mostly done by /etc/sysconfig/network (only valid for Red Hat like distributions). If you enable a built-in service like e.g. daytime by modifying the configuration file in /etc/xinetd.d/daytime like After restarting the xinetd you should get a positive result like: Shown example also displays an IMAP and IMAP-SSL IPv4-only listening xinetd. Note: An IPv4-only xinetd won't start on an IPv6-enabled node and also the IPv6-enabled won't start on an IPv4-only node (will be hopefully fixed in the future). Webserver Apache2 (httpd2) Apache web server supports IPv6 native by maintainers since 2.0.14. Available patches for the older 1.3.x series are not current and shouldn't be used in public environment, but available at KAME / Misc. Listening on IPv6 addresses Note: virtual hosts on IPv6 addresses are broken in versions until 2.0.28 (a patch is available for 2.0.28). But always try latest available version first because earlier versions had some security issues. Virtual host listen on an IPv6 address only ]]> ]]> Virtual host listen on an IPv6 and on an IPv4 address ]]> ]]> This should result after restart in e.g. For simple tests use the telnet example already shown. Additional notes Apache2 supports a method called "sendfile" to speedup serving data. Some NIC drivers also support offline checksumming. In some cases, this can lead to connection problems and invalid TCP checksums. In this cases, disable "sendfile" either by recompiling using configure option "--without-sendfile" or by using the "EnableSendfile off" directive in configuration file. Router Advertisement Daemon (radvd) The router advertisement daemon is very useful on a LAN, if clients should be auto-configured. The daemon itself should run on the Linux default IPv6 gateway router (it's not required that this is also the default IPv4 gateway, so pay attention who on your LAN is sending router advertisements). You can specify some information and flags which should be contained in the advertisement. Common used are Prefix (needed) Lifetime of the prefix Frequency of sending advertisements (optional) After a proper configuration, the daemon sends advertisements through specified interfaces and clients are hopefully receive them and auto-magically configure addresses with received prefix and the default route. Configuring radvd Simple configuration Radvd's config file is normally /etc/radvd.conf. An simple example looks like following: This results on client side in mtu 1500 qdisc pfifo_fast qlen 100 ]]> Because no lifetime was defined, a very high value was used. Special 6to4 configuration Version since 0.6.2pl3 support the automatic (re)-generation of the prefix depending on an IPv4 address of a specified interface. This can be used to distribute advertisements in a LAN after the 6to4 tunneling has changed. Mostly used behind a dynamic dial-on-demand Linux router. Because of the sure shorter lifetime of such prefix (after each dial-up, another prefix is valid), the lifetime configured to minimal values: This results on client side in (assuming, ppp0 has currently 1.2.3.4 as local IPv4 address): mtu 1500 qdisc pfifo_fast qlen 100 ]]> Because a small lifetime was defined, such prefix will be thrown away quickly, if no related advertisement was received. Debugging A program called "radvdump" can help you looking into sent or received advertisements. Simple to use: Output shows you each advertisement package in readable format. You should see your configured values here again, if not, perhaps it's not your radvd which sends the advertisement...look for another router on the link (and take the LLAddress, which is the MAC address for tracing). tcp_wrapper tcp_wrapper is a library which can help you to protect service against misuse. Filtering capabilities You can use tcp_wrapper for Filtering against source addresses (IPv4 or IPv6) Filtering against users (requires a running ident daemon on the client) Which program uses tcp_wrapper Following are known: Each service which is called by xinetd (if xinetd is compiled using tcp_wrapper library) sshd (if compiled using tcp_wrapper) Usage tcp_wrapper is controlled by two files name /etc/hosts.allow and /etc/hosts.deny. For more information see Example for /etc/hosts.allow In this file, each service which should be positive filtered (means connects are accepted) need a line. Note: there are broken implementations around, which uses following broken IPv6 network description: [3ffe:ffff:100:200::/64]. Hopefully, such versions will be fixed soon. Example for /etc/hosts.deny This file contains all negative filter entries and should normally deny the rest using If this node is a more sensible one you can replace the standard line above with this one, but this can cause a DoS attack (load of mailer and spool directory), if too many connects were made in short time. Perhaps a logwatch is better for such issues. Logging Depending on the entry in the syslog daemon configuration file /etc/syslog.conf the tcp_wrapper logs normally into /var/log/secure. Refused connection A refused connection via IPv4 to an xinetd covered daytime service produces a line like following example A refused connection via IPv4 to an dual-listen sshd produces a line like following example Permitted connection A permitted connection via IPv4 to an xinetd covered daytime service produces a line like following example A permitted connection via IPv4 to an dual-listen sshd produces a line like following example Programming (using API) I have no experience in IPv6 programming, perhaps this chapter will be filled by others or moved away to another HOWTO. More Information can be found here: RFC 2553 / Basic Socket Interface Extensions for IPv6 Draft / Advanced Sockets API for IPv6 / draft-ietf-ipngwg-rfc2292bis-XY.txt Interoperability There are some projects around the world which checks the interoperability of different operating systems regarding the implementation of IPv6 features. Here some URLs: TAHI Project More coming next... Further information and URLs Paper printed books, articles, online reviews (mixed) Printed Books (English) Cisco Cisco Self-Study: Implementing IPv6 Networks (IPV6), by Regis Desmeules. Cisco Press; ISBN 1587050862; 500 pages; 1st edition (April 11, 2003). Note: This item will be published on April 11, 2003. Configuring IPv6 with Cisco IOS, by Sam Brown, Sam Browne, Neal Chen, Robbie Harrell, Edgar, Jr. Parenti (Editor), Eric Knipp (Editor), Paul Fong (Editor)362 pages; Syngress Media Inc; ISBN 1928994849; (July 12, 2002). General IPv6 Essentials by Silvia Hagen, July 2002, O'Reilly Order Number: 1258, ISBN 0-5960-0125-8, 352 pages. ToC, Index, Sample Chapter etc.; O'Reilly Pressrelease IPv6: The New Internet Protocol. By Christian Huitema; Published by Prentice-Hall; ISBN 0138505055. Description: This book, written by Christian Huitema - a member of the InternetArchitecture Board, gives an excellent description of IPv6, how it differs from IPv4, and the hows and whys of it's development. Source: http://www.cs.uu.nl/wais/html/na-dir/internet/tcp-ip/resource-list.html IPv6 Networks by Niles, Kitty; (ISBN 0070248079); 550 pages; Date Published 05/01/1998. Implementing IPV6. Supporting the Next Generation Internet Protocols by P. E. Miller, Mark A. Miller; Publisher: John Wiley & Sons; ISBN 0764545892; 2nd edition (March 15, 2000); 402 pages. Big Book of Ipv6 Addressing Rfcs by Peter H. Salus (Compiler), Morgan Kaufmann Publishers, April 2000, 450 pages ISBN 0126167702. Understanding IPV6 by Davies, Joseph; ISBN 0735612455; Date Published 05/01/2001; Number of Pages: 350. Understanding IPV6 by Davies, Joseph; ISBN 0735612455; Date Published 13/11/2002; Number of Pages 544. Migrating to IPv6 - IPv6 in Practice. By Marc Blanchet Publisher: John Wiley & Sons; ISBN 0471498920; 1st edition (November 2002); 368 pages. Programming IPv6 by Sean Walton; 560 pages; Addison-Wesley Professional; ISBN 0672323443 Note: Will be published August 1, 2003. Wireless boosting IPv6 by Carolyn Duffy Marsan, 10/23/2000. O'reilly Network search for keyword IPv6 results in 29 hits (28. January 2002). Printed Books (German) Technik der IP-Netze (TCP/IP incl. IPv6) bei Amazon.de Anatol Badach, Erwin Hoffmann Carl Hanser Verlag München, Wien, 2001 ISBN 3-446-21501-8 Kap. 6: Protokoll IPv6 S.205-242 Kap. 7: Plug&Play-Unterstützung bei IPv6 S.243-276 Kap. 8: Migration zum IPv6-Einsatz S.277-294 Kap. 9.3.4: RIP für das Protokoll IPv6 (RIPng) S.349-351 Kap. 9.4.6: OSPF für IPv6 S.384-385 Kommentar: tw. nicht ganz up-to-date bzw. nicht ganz fehlerfreie Abbildungen Homepage des Buches und Tabelle mit Fixes Internet-Sicherheit (Browser, Firewalls und Verschlüsselung) bei Amazon.de Kai Fuhrberg 2. akt. Auflage 2000 Carl Hanser Verlag München, Wien, ISBN 3-446-21333-3 Kap.2.3.1.4. IPv6 S.18-22 Kurz angerissen werden: RFC1825 - Security Association Konzept RFC1826 - IP authentication Header RFC1827 - IP Encapsulation Security Payload IPv6. Das neue Internet- Protokoll. Technik, Anwendung, Migration bei Amazon Hans Peter Dittler 2. akt. und erweiterte Auflage 2002 dpunkt.verlag, ISBN 3-89864-149-X Das neue Internetprotokoll IPv6 bei Amazon Herbert Wiese 2002 Carl Hanser Verlag, ISBN 3446216855 Articles, eBooks, Online Reviews (mixed) Getting Connected with 6to4 by Huber Feyrer, 06/01/2001 How Long the Aversion to IP Version 6 - Review of META Group, Inc., full access needs (free) registration at META Group, Inc. Transient Addressing for Related Processes: Improved Firewalling by Using IPv6 and Multiple Addresses per Host; written by Peter M. Gleiz, Steven M. Bellovin (PC-PDF-Version; Palm-PDF-Version; PDB-Version) IPv6, théorie et pratique (french) 3e édition, mars 2002, O'Reilly, ISBN 2-84177-139-3 IPSec (language: french) Internetworking IPv6 with Cisco Routers by Silvano Gai, McGrawHill Italia, 1997. The 13 chapters and appendix A-D are downloadable as PDF-documents. Secure and Dynamic Tunnel Broker by Vegar Skaerven Wang, Master of Engineering Thesis in Computer Science, 2.June 2000, Faculty of Science, Dep.of Computer Science, University of Tromso, Norway. Aufbruch in die neue Welt - IPv6 in IPv4 Netzen von Dipl.Ing. Ralf Döring, TU Illmenau, 1999 Migration and Co-existence of IPv4 and IPv6 in Residential Networks by Pekka Savola, CSC/FUNET, 2002 Science Publications (abstracts, bibliographies, online resources) Standardisation Report, December 2002 published by IPv6 Cluster, 1mb (every 4 months the Standards report will be updated under: http://www.ist-ipv6.org/standards.html). GEANT IPv6 Workplan Mobility support in IPv6 by C.E. Perkins and D.B. Johnson. In Proceedings of the Second Annual International Conference on Mobile (1996). A simulation study on the performance of Mobile IPv6 in a WLAN-based cellular network, by Perez Costa X.; Hartenstein H. -- Computer Networks, September 2002, vol. 40, no. 1, pp. 191-204(14) -- Elsevier Science. IPv6 Trials on UK Academic Networks: Bermuda Project Aug.2002: Participants - Getting connected - Project deliverables - Network topology - Address assignments - Wireless IPv6 access - IPv6 migration - Project presentations - Internet 2 - Other IPv6 projects - IPv6 fora and standards Bermuda 2... http://www.ipv6.ac.uk/ A scalable parallel internet router that enables the QoS through merging ATM with IPv6. By Song S. -- Computer Communications, 1 May 2002, vol. 25, no. 7, pp. 647-651(5) -- Elsevier Science. Linux IPv6: Which One to Deploy? Linux Journal, Vol. 96, p. 86, 88-90, April 2002. An overview and analysis of mobile Internet protocols in cellular environments. Chao H-C. -- Internet Research: Electronic Networking Applications and Policy, 24 October 2001, vol. 11, no. 5, pp. 435-450(16) -- MCB University Press IPv6 for Future Wireless NetworksToftegaard Nielsen T. -- Wireless Personal Communications, June 2001, vol. 17, no. 2/3, pp. 237-247(11) -- Kluwer Academic Publishers, Dordrecht, The Netherlands IPv6 at the University of Southampton Seamless Support for Mobile Internet Protocol Based Cellular EnvironmentsChao H-C.; Chu Y-M. -- International Journal of Wireless Information Networks, July 2001, vol. 8, no. 3, pp. 133-153(21) -- Kluwer Academic/Plenum Publishers, New York, U.S.A. IPv6: The Solution for Future Universal Networks. Lecture Notes in Computer Science, Vol. 1818, p. 82-??, 2000. Modeling and performance analysis for IPv6 traffic with multiple QoS classes. Zhang L.; Zheng L. -- Computer Communications, 1 October 2001, vol. 24, no. 15, pp. 1626-1636(11) -- Elsevier Science. Threshold-Based Registration (TBR) in Mobile IPv6. Lecture Notes in Computer Science, Vol. 1818, p. 150-??, 2000. IPv6 Performance Analysis on FreeBSD Workstation Using Simple Applications. Lecture Notes in Computer Science, Vol. 1961, p. 33-??, 2000. Microsoft Research IPv6 Implementation (MSRIPv6): MSRIPv6 Configuring 6to4 - Connectivity with MSR IPv6 - Our 6Bone Node... New frontiers in cybersegmentation: marketing success in cyberspace depends on IP address. Louvieris P.; Driver J. -- Qualitative Market Research: An International Journal, 27 June 2001, vol. 4, no. 3, pp. 169-181(13) -- MCB University Press. QoS-Conditionalized Handoff for Mobile IPv6. Lecture Notes in Computer Science, Vol. 2345, p. 721-??, 2002. Others See following URL for more: SWITCH IPv6 Pilot / References Conferences, Meetings, Summits 2002 Renater - Conférence IPv6 2002 IPv6 Deployment Summit at INET 2002 Something missing? Suggestions are welcome! 2003 Suggestions are welcome! Online information Join the IPv6 backbone More to be filled later...suggestions are welcome! Global registries IPv6 test backbone: 6bone, How to join 6bone, Teilnahme am 6bone (german language), 6bone participation (english language) Major regional registries America: ARIN, ARIN / registration page, ARIN / IPv6 guidelines EMEA: Ripe NCC, Ripe NCC / registration page, Ripe NCC / IPv6 registration Asia/Pacific: APNIC, APNIC / IPv6 ressource guide Latin America and Caribbea: LACNIC, IPv6 Registration Services, IPv6 Allocation Policy Africa: AfriNIC Also a list of major (prefix length 35) allocations per local registry is available here: Ripe NCC / IPv6 allocations. Tunnel brokers Note: A list of available Tunnel broker can be found in the section Tunnel broker below. Sourcecode used in Vermicellis Master thesis about tunnelbroker, University of Tromso. Former IPng. Tunnelbroker and IPv6 resources, now migrated to the SixXs System. Eckes' IPv6-with-Linux Page. RIPE6.net: Configure an IPv6 Tunnel to a tunnelbroker; Route ipv6-ips from your router to other clients in your network... tunnelc - a perl based tunnel client script: freshmeat.net: Project details for tunnel client SourceForge: Project Info - tunnelc (also here) Tunnelbroker Maillingliste Linux Advanced Routing & Traffic Control HOWTO, Chapter 6: IPv6 tunneling with Cisco and/or 6bone. See also here for more information and URLs: ipv6-net.org. 6to4 NSayer's 6to4 information RFC 3068 / An Anycast Prefix for 6to4 Relay Routers Latest news More to be filled later...suggestions are welcome! hs247 / IPv6 news and information bofh.st / latest IPv6 news (but currently [Jan 2002] outdated...), also homepage for #IPv6 channel on IRCnet ipv6-net.org, German forum Protocol references IPv6-related Request For Comments (RFCs) Publishing the list of IPv6-related RFCs is beyond the scope of this document, but given URLs will lead you to such lists: List sorted by IPng Standardization Status or IPng Current Specifications by Robert Hinden IPv6 Related Specifications on IPv6.org Current drafts of working groups Current (also) IPv6-related drafts can be found here: IP Version 6 (ipv6) Next Generation Transition (ngtrans) Dynamic Host Configuration (dhc) Domain Name System Extension (dnsext) Mobile IP (mobileip) Get any information about IPv6, from overviews, through RFCs & drafts, to implementations (including availability of stacks on various platforms & source code for IPv6 stacks) IPv6 specifications - Latest RFCs and Internet Drafts Collection. Others Network Sorcery / IPv6, Internet Protocol version 6, IPv6 protocol header SWITCH IPv6 Pilot / References, big list of IPv6 references maintained by Simon Leinen Advanced Network Management Laboratory / IPv6 Address Oracle shows you IPv6 addresses in detail More information More to be filled later...suggestions are welcome! DeepSpace6 / more interesting links Linux related DeepSpace6 / (Not only) Linux IPv6 Portal - Italy (Mirror) IPv6-HowTo for Linux by Peter Bieringer - Germany, and his Bieringer / IPv6 - software archive Linux+IPv6 status by Peter Bieringer - Germany (going obsolete) DeepSpace6 / IPv6 Status Page - Italy (Mirror) (will superseed upper one) USAGI project - Japan, and their USAGI project - software archive Gav's Linux IPv6 Page Linux related per distribution PLD PLD Linux Distribution ("market leader" in containing IPv6 enabled packages) Red Hat Red Hat Linux, Pekka Savola's IPv6 packages Debian Debian Linux, Craig Small's IPv6 information and status, Jim's insignificant LAN IPv6 global connectivity HOWTO SuSE SuSE Linux Mandrake Linux Mandrake For more see the IPv6+Linux Status Distributions page. General IPv6.org 6bone UK IPv6 Resource Centre - UK JOIN: IPv6 information - Germany, by the JOIN project team maintaining also Links to external WWW pages comprising IPv6/IPng. TIPSTER6 project - Hungary, "Testing Experimental IPv6 Technology and Services in Hungary". WIDE project - Japan SWITCH IPv6 Pilot - Switzerland IPv6 Corner of Hubert Feyrer - Germany Vermicelli Project - Norway IPv6 Forum - a world-wide consortium of leading Internet vendors, Research & Education Networks... Playground.sun.com / IPv6 Info Page - maintained by Robert Hinden, Nokia. Get any information about IPv6, from overviews, through RFCs & drafts, to implementations (including availability of stacks on various platforms & source code for IPv6 stacks). NASA Ames Research Center (old content) 6INIT - IPv6 Internet Initiative - an EU Fifth Framework Project under the IST Programme. IPv6 Task Force (European Union) IPv6 Document Project (Japanese language) 6init - IPv6 INternet IniTiative IP Next Generation Overview The IPng Group's home page. IPv6: The New Version of the Internet Protocol, by Steve Deering. IPv6: The Next Generation Internet Protocol, by Gary C. Kessler. IPv6: Next Generation Internet Protocol - 3Com Literature Research IPv6 (IPng), by Mike Crawfurd. Next Generation Internet Initiative internet || site and internet2 Working Group - Presentation (HTML + PPT) from IPv6 Workshops: (Stateless Autoconfiguration, IPv6 Addressing, USAGI, Provider Independent IPv6 Addressing and other topics). NetworkWorldFusion: Search / Doc Finder: searched for IPv6 (102 documents found 22.12.2002) The Register (Search for IPv6 will result in 30 documents, 22.12.2002) ZDNet Search for IPv6 TechTarget Search for IPv6 IPv6 & TCP Resources List Klingon IPv6 tools, Klingon IPv6 tools (native IPv6 only access): IPv6 firewall examples, bandwith testing and portscanner Something missing? Suggestions are welcome! Market Research A Tale of Two Wireless Technology Trends: Processor Development Outsourcing and IPv6Yankee Group - 4/1/2002 - 12 Pages - ID: YANL768881 The World Atlas of the Internet: Americas; IDATE - 2/1/2002 - 242 PAges - ID: IDT803907. Countries covered: Central America, North America, South America; List: Price: $ 3,500.00; excerpt: Panorama of Internet access markets across the globe. Market assessment and forecasts up to 2006 for 34 countries: market structure: main ISPs and market shares; number of subscribers, of ISPs. Early Interest Rising for IPv6 by IDC (Author); List Price: $1,500.00; Edition: e-book (Acrobat Reader); Publisher: IDC; ISBN B000065T8E; (March 1, 2002) Patents Canadian Patent Database: Home, Search (Basic Search, just enter IPv6 in the search field ;-); 84 documents found 22.12.2002) Espacenet - European patent information: National Offices, Members of Espacenet(IPv6: 84 documents, 22.12.2002) Delphion Research: Patent Search Page. Basic (free) registration needed. Examples found 21.12.2002 searching for IPv6: Communicating method between IPv4 terminal and IPv6 terminal and IPv4-IPv6 converting apparatus Translator for IP networks, network system using the translator, and IP network coupling method therefor By countries Austria IPv6@IKNnet and MIPv6 Research Group: TU Vienna, Austria (IPv6: project, publications, diploma / doctor thesis, Conference Proceedings etc.) Australia Carl's Australian IPv6 Pages (old content) Belgium BELNET: the Belgian Research Network Euronet: one of the biggest ISP's of Belgium... Brasilia BR6bone China Nokia China - IPv6 Site Internet6 Initiative by Nokia China Czech IPv6 in Czech On Line Germany IPv6-net.org: German IPv6 forum France Renater: Renater IPv6 Project Page IPv6 - RSVP - ATM at INRIA NetBSD IPv6 Documentation Hungary Testing Experimental IPv6 Technology and Services in Hungary Hungarian IPv6 Information Page India IPv6 at BITS Italy Project6: IPv6 networking with Linux Edisontel: IPv6 Portal of Edisontel Japan Linux IPv6 Users Group JP Yamaha IPv6 (sorry, all in japanese native ...) Korea ETRI: Electronics and Telecommunications Research Institut IPv6 Forum Korea: Korean IPv6 Deployment Project Mexico IPv6 Mexico (spain & english version): IPv6 Project Hompeage of The National Autonomous University of Mexico (UNAM) Netherland SURFnet: SURFnet IPv6 Backbone STACK, STACK (IPv6): Students' computer association of the Eindhoven University of Technology, Netherland IPng.nl: collaboration between WiseGuys and Intouch Portugal IPv6 pages of Miguel Rosa (broken?) FCCN (National Foundation for the Scientific Computation) University of Algarve, Portugal IPv6 - MFA Russia IPv6 Forum for Russia: Yaroslavl State University Internet Center Switzerland SWITCH: The Swiss Education & Research Network United Kingdom IPv6 in the UK UK IPv6 Resource Center British Telecom IPv6 Home: BT's ISP IPv6 Trial, UK's first IPv6 Internet Exchange etc. By operating systems *BSD KAME project (*BSD) NetBSD's IPv6 Networking FAQ FreeBSD Documentation Project FreeBSD Ports: Ipv6 BUGAT - BSD Usergroup Austria - www.bugat.at: FreeBSD IPv6 Tunnel (German language) Cisco IOS Cisco IOS IPv6 Entry Page IPv6 for Cisco IOS Software, File 2 of 3: Aug 2002 -- Table of Contents: IPv6 for Cisco IOS Software; Configuring Documentation Specifics; Enabling IPv6 Routing and Configuring; IPv6 Addressing; Enabling IPv6 Processing Globally. Cisco Internet Networking Handbook, Chapter IPv6 Compaq IPv6 at Compaq - Presentations, White Papers, Documentation... HPUX comp.sys.hp.hpux FAQ IBM Now that IBM's announced the availability of z/OS V1.4, what's new in this release? This question was posed on 15 August 2002 Microsoft Microsoft Windows 2000 IPv6 MSRIPv6 - Microsoft Research Network - IPv6 Homepage Getting Started with the Microsoft IPv6 Technology Preview for Windows 2000 Internet Connection Firewall Does Not Block Internet Protocol Version 6 Traffic (6.11.2001) Internet Protocol Numbers (8.10.2002) IPv6 Technology Preview Refresh (16.10.2002) HOW TO: Install and Configure IP Version 6 in Windows .NET Enterprise Server (26.10.2002) Windows .NET Server 6to4 Router Service Quits When You Advertise a 2002 Address on the Public Interface (28.10.2002) msdn - Microsoft Windows CE .NET - IPv6 commands msdn - search for IPv6 (100 results, 22.12.2002) Solaris Sun Microsystems IPv6 Page for Solaris 8 Solaris 2 Frequently Asked Questions (FAQ) 1.73 Sumitoma Sumitomo Electric has implemented IPv6 on Suminet 3700 family routers ZebOS IpInfusion's ZebOS Server Routing Software IPv6 Security Internet Security Systems: Security Center, X-Force Database Search (21.12.2002 - 6 topics found relating to IPv6) NIST IPsec Project ( National Institute of Standards and Technology, NIST) Information Security, Search for IPv6 (21.12.2002 - 9 articles found) NewOrder.box.sk (search for IPv6) (Articles, exploits, files database etc.) Application lists IPv6.org / IPv6 enabled applications Freshmeat / IPv6 search, currently (14 Dec 2002) 62 projects IPv6 Forum: IPv6 Router List Analyzer tools Ethereal - Ethereal is a free network protocol analyzer for Unix and Windows Radcom RC100-WL - Download Radcom RC100-WL protocol analyzer version 3.20 IPv6 Products 6wind - solutions for IPv4/IPv6 Router, QoS, Multicast, Mobility, Security/VPN/Firewall. Fefe's patches for IPv6 with djbdnsAug 2002 -- What is djbdns and why does it need IPv6? djbdns is a full blown DNS server which outperforms BIND in nearly all respects. Hitachi, Ltd. IPv6 Home PageIPv6 Products GR2000 - IPv6 router; Toolnet6 - Protocol Exchange software for IPv6. ZebOS Server Routing Suite SPA Mail Server 2.21 Inframail (Advantage Server Edition) 4.0 HTTrack Website Copier 3.2 CommView 3.4 Posadis 0.50.6 Xceed Winsock Library 1.2 CommView 3.4 TCP Wrapper (IPv6 aware) SNMP comp.protocpols.snmp SNMP FAQ Part 1 of 2 IPv6 Infrastructure Statistics IPv6 routing table history created by Gert Döring, Space.Net Usage Statistics for www6.vermicelli.pasta.cs.uit.no (last 12 months) Official 6bone Webserver list Statisic IPv6 Allocation Data & Survey Results, IPv6 WG, Ripe 42, Ripe NCC Internet Exchanges Another list of IPv6 Internet Exchanges can be found here: IPv6 Exchanges Web Site Estonia TIX (tallinn interneti exchange with ipv6 support) Europe Euro6IX, European IPv6 Internet Exchange Backbone France French National Internet Exchange IPv6 (since 1.11.2002 active). FNIX6 provides a free and reliable high speed FastEthernet interconnection between ISP located in TeleCity Paris. Germany INXS: (Cable & Wireless) Munich and Hamburg Japan NSPIXP-6: IPv6-based Internet Exchange in Tokyo JPIX, Tokyo Korea 6NGIX Netherlands AMS-IX: Amsterdam Internet Exchange UK UK6X: London XchangePoint: London USA 6TAP: Chicago. Supports peerings around the globe. NY6IX: New York City IPv6 based Internet Exchange 6IIX: New York, Los Angeles and Santa Clara PAIX: Palo Alto Tunnel broker Belgium Wanadoo Canada Freenet6 - /48 Delegation, Canada Getting IPv6 Using Freenet6 on Debian Freenet6 creater China CERNET-Nokia Estonia Estpak Europe XS26 Distributed Tunnel Broker, USA & Europe Germany JOIN, University of Münster Tunnelbroker Leipzig, Germany - DialupUsers with dynamic IP's can get a fix IPv6 IP... JOIN, Tunnelbroker Leipzig, (currently offline ?) Das offizielle IPv6 Forum, Leipziger Tunnelbroker Experimental Live IPv6 Stream! 6bone Knoten Leipzig Info bez. Hackangriff (2001) Tunnelbroker for JOIN. This tunnel broker is only available for students and staff members of colleges and universities Berkom Italy Centro Studi e Laboratory Telecomunicazioni ( Downloadpage: TunnelBroker Version 2.1.) IPv6 Tunnel Broker: Installation instructions EdisonTel Comv6 Bersafe (Italian language) Telecom Italia LAB (Tunnelbroker Software Downloadpage) Japan Internet Initiative Japan (Japanese language) - with IPv6 native line service and IPv6 tunneling Service Malaysia Manis Netherlands XS26 - "Access to Six" - with POPs in Slovak Republic, Czech Republic, Netherlands, Germany and Hungary. IPng Netherland - Intouch, SurfNet, AMS-IX, UUNet, Cistron, RIPE NCC and AT&T are connected at the AMS-IX. It is possible (there are requirements...) to get an static tunnel. SURFnet Customers Norway UNINETT, Norway - Pilot IPv6 Service (for Customers): tunnelbroker & address allocation UNINETT's Tunnel Broker (link correct, but inavailable - 23.12.2002) Uninett-Autoupdate-HOWTO Switzerland Tunnelbroker AS8758, Dolphins Network Systems (since 20.12.2002 online) UK NTT Europe, NTT, United Kingdom - IPv6 Trial. IPv4 Tunnel and native IPv6 leased Line connections. POPs are located in London, UK Dusseldorf, Germany New Jersey, USA (East Coast) Cupertino, USA (West Coast) Tokyo, Japan BtexacT IPv6 Tunnel Broker Service IPNG-UK USA ESnet, USA - Energy Sciences Network: Tunnel Registry & Address Delegation for directly connected ESnet sites and ESnet collaborators. 6REN, USA - The 6ren initiative is being coordinated by the Energy Sciences Network (ESnet), the network for the Energy Research program of the US Dept. of Energy, located at the University of California's Lawrence Berkeley National Laboratory. XS26 Distributed Tunnel Broker, USA & Europe Hurricane Electric, US backbone; Hurrican Electric Tunnelbroker (also available under http://tunnelbroker.com/) Press Release: Hurricane Electric Upgrades IPv6 Tunnel Broker Tunnel Broker Endpoint Autoupdate, Perl Script Mondo Services DHIS Dynamic Tunnel, Dynamic Host Information System, University of Bradford More Tunnel brokers... Public 6to4 relay routers (MS IIE boycott!) Native IPv6 Services Note: These services are only available with a valid IPv6 connection! Game Server Quake2 over IPv6 IRC Server Cyconet (Cyconet IRCnet Servers over IPv6) Radio Stations, Music Streams Experimental Live IPv6 Stream!, University of Leipzig, Germany Webserver Peter Bieringer's Home of Linux IPv6 HOWTO Something missing? Suggestions are welcome! Maillists Lists of maillists are available at: JOIN Project / List of IPv6-related maillists DeepSpace6 / Mailling Lists Major Mailinglists are listed in following table: . Focus Request e-mail address What to subscribe Maillist e-mail address Language Access through WWW Linux kernel networking including IPv6 majordomo (at) oss.sgi.com netdev netdev (at) oss.sgi.com English Archive Linux and IPv6 in general (1) majordomo (at) list.f00f.org linux-ipv6 linux-ipv6 (at) list.f00f.org (moderated) English Linux implementation of the IPv6 protocol Web-based, see URL project6 (at) ferrara.linux.it English Info, Subscription Mobile IP(v6) for Linux majordomo (at) list.mipl.mediapoli.com mipl mipl (at) list.mipl.mediapoli.com English Info, Archive Linux IPv6 users using USAGI extension usagi-users-ctl (at) linux-ipv6.org usagi-users (at) linux-ipv6.org English Info / Search, Archive IPv6 on Debian Linux Web-based, see URL debian-ipv6 (at) lists.debian.org English Info/Subscription/Archive IPv6/6bone in Germany majordomo (at) atlan.uni-muenster.de ipv6 ipv6 (at) uni-muenster.de German/English Info, Archive 6bone majordomo (at) isi.edu 6bone 6bone (at) isi.edu English Info, Archive IPv6 discussions majordomo (at) sunroof.eng.sun.com ipng ipng (at) sunroof.eng.sun.com English Info, Archive, Mirror of archive IPv6 users in general majordomo (at) ipv6.org users users (at) ipv6.org English Info, Archive Bugtracking of Internet applications (2) bugtraq-subscribe (at) securityfocus.com bugtraq (at) securityfocus.com (moderated) English Info, Archive IPv6 in general Web-based, see URL ipv6 (at) ipng.nl English Info/Subscription, Archive majordomo (at) mfa.eti.br majordomo (at) mfa.eti.br ipv6 ipv6 (at) mfa.eti.br Portuguese Info (1) recommended for common Linux & IPv6 issues. (2) very recommended if you provide server applications. Something missing? Suggestions are welcome! Following other maillinglists & newsgroups are available via web: ipv6 (France) Description: ipv6 Cette liste existe pour discuter en francais de IP version 6. Elle s'adresse aux personnes desirant demarer des aujourd'hui des tests IPv6. Ce n'est en aucun cas un substitut des listes de l'IETF. Pour de plus amples informations: http://www.urec.fr/IPng Tunnelbroker Maillingliste (Germany) ipv6 (Hungary) Description: ipv6 Az IPv6 protokoll listaja Konfiguracios es adminisztracios kerdesek az IPv6-al kapcsolatban. (Archivum) student-ipv6 (India) Description: This is the group for the Student Awareness group of IPv6 in India IPV6-CNR@LISTSERV.CNR.IT (Italy) Description: Gruppo di interesse IPv6 del CNR ipv6-jp (Japan) ipv6 (Japan) IPV6@LISTS.UTWENTE.NL (Netherlands) Description: IPv6 overleg IPV6@NIC.SURFNET.NL (Netherlands) Description: AMS-IX list for IPv6 related matters sun-ipv6-users Description: Please report problems/suggestions regarding SUN Microsystems IPng implementation IPv6-BITS Description: This List will co-ordinate the working of Project Vertebrae. openbsd-ipv6 IPv6 Description: This mailing list is for technical discussion of the possibilities of ipv6/ipsec WRT OpenBSD. linux-bangalore-ipv6 Description: The IPv6 deployment list of the Bangalore Linux User Group gab Description: The intent is to discuss geographic addressing plans for IPv6. ipv6-bsd-user Description: This mailing list is about the INRIA/IMAG IPv6 implementation. Cette liste de discussion est au sujet de l'implementation INRIA/IMAG IPv6. Elle est bilingue Francais/Anglais. The mailing list is biligual, French & English. If you wish to contact the implementors, try ipv6-bsd-core@imag.fr Si vous voulez contacter les implementeurs, essayez ipv6-bsd-core@imag.fr gated-ipv6 packet-switching Description: This mailing list provides a forum for discussion of packet switching theory, technology, implementation and application in any relevant aspect including without limitation LAPB, X.25, SDLC, P802.1d, LLC, IP, IPv6, IPX, DECNET, APPLETALK, FR, PPP, IP Telephony, LAN PBX systems, management protocols like SNMP, e-mail, network transparent window systems, protocol implementation, protocol verification, conformance testing and tools used in maintaining or developing packet switching systems. mumbaiinternetgroup Description: This Forum will discuss current issues & developments in the field of Internet In Asia Pacific region.. This will cover discussion on..IPv4, IPv6, Multilingual DNS, Autonomous System Numbers, Internet Governence & Much more.... de.comm.protocols.tcp-ip Description: Umstellung auf IPv6 Source: Chartas der Newsgruppen in de.* Hurricane Electric IPv6 Forum Google Group: comp.protocols.tcp-ip Google Group: linux.debian.maint.ipv6 Google Group: microsoft.public.platformsdk.networking.ipv6 Google Group: fa.openbsd.ipv6 Online test tools More to be filled later...suggestions are welcome! finger, nslookup, ping, traceroute, whois: UK IPv6 Resource Centre / The test page ping, traceroute, tracepath, 6bone registry, DNS: JOIN / Testtools (German language only, but should be no problem for non German speakers) traceroute6, whois: IPng.nl 6BONE Registry List of worldwide all IPv6-aggregated IP-Blocks (daily update) same service from Ripe IPv6 Looking Glasses IMAG, France IPv6 Looking Glass at SURRIEL APAN, Japan (APAN-JP) DRENv6 Looking Glass Trainings, Seminars IPv6 Training and Workshop, AERAsec, Germany (German language only at this time) Migrating to IPv6, Learning Tree International CIW Internetworking Professional Training CBT CD Training Pages, U.K. - Search for IPv6 (13 Courses, 22.12.2002) Something missing? Suggestions are welcome! 'The Online Discovery' ... IPv6: Addressing The Needs Of the Future [DOWNLOAD: PDF] by Yankee Group (Author) List Price: $595.00 Edition: e-book (Acrobat Reader) Pages: 3 (three) Publisher: MarketResearch.com; ISBN B00006334Y; (November 1, 2001) ;-) The number of copies would be interesting... Revision history / Credits / The End Revision history Versions x.y are published on the Internet. Versions x.y.z are work-in-progress and only published as LyX file on CVS. Releases 0.x 0.44 2003-08-15/PB: fix URLs, add hint on tcp_wrappers (about broken notation in some versions) and Apache2 0.43.4 2003-07-26/PB: fix URL, add archive URL for maillist users at ipv6.org, add some ds6 URLs 0.43.3 2003-06-19/PB: fix typos 0.43.2 2003-06-11/PB: fix URL 0.43.1 2003-06-07/PB: fix some URLs, fix credits, add some notes at IPsec 0.43 2003-06-05/PB: add some notes about configuration in SuSE Linux, add URL of French translation 0.42 2003-05-09/PB: minor fixes, announce French translation 0.41.4 2003-05-02/PB: Remove a broken URL, update some others. 0.41.3 2003-04-23/PB: Minor fixes, remove a broken URL, fix URL to Taiwanese translation 0.41.2 2003-04-13/PB: Fix some typos, add a note about a French translation is in progress 0.41.1 2003-03-31/PB: Remove a broken URL, fix another 0.41 2003-03-22/PB: Add URLof German translation 0.40.2 2003-02-27/PB: Fix a misaddressed URL 0.40.1 2003-02-12/PB: Add Debian-Linux-Configuration, add a minor note on translations 0.40 2003-02-10/PB: Announcing available German version 0.39.2 2003-02-10/GK: Minor syntax and spelling fixes 0.39.1 2003-01-09/PB: fix an URL (draft adopted to an RFC) 0.39 2003-01-13/PB: fix a bug (forgotten 'link" on "ip link set" (credits to Yaniv Kaul) 0.38.1 2003-01-09/PB: a minor fix 0.38 2003-01-06/PB: minor fixes 0.37.1 2003-01-05/PB: minor updates 0.37 2002-12-31/GK: 270 new links added (searched in 1232 SearchEngines) in existing and 53 new (sub)sections 0.36.1 2002-12-20/PB: Minor fixes 0.36 2002-12-16/PB: Check of and fix broken links (credits to Georg Käfer), some spelling fixes 0.35 2002-12-11/PB: Some fixes and extensions 0.34.1 2002-11-25/PB: Some fixes (e.g. broken linuxdoc URLs) 0.34 2002-11-19/PB: Add information about German translation (work in progress), some fixes, create a small shortcut explanation list, extend "used terms" and add two German books 0.33 2002-11-18/PB: Fix broken RFC-URLs, add parameter ttl on 6to4 tunnel setup example 0.32 2002-11-03/PB: Add information about Taiwanese translation 0.31.1 2002-10-06/PB: Add another maillist 0.31 2002-09-29/PB: Extend information in proc-filesystem entries 0.30 2002-09-27/PB: Add some maillists 0.29 2002-09-18/PB: Update statement about nmap (triggered by Fyodor) 0.28.1 2002-09-16/PB: Add note about ping6 to multicast addresses, add some labels 0.28 2002-08-17/PB: Fix broken LDP/CVS links, add info about Polish translation, add URL of the IPv6 Address Oracle 0.27 2002-08-10/PB: Some minor updates 0.26.2 2002-07-15/PB: Add information neighbor discovery, split of firewalling (got some updates) and security into extra chapters 0.26.1 2002-07-13/PB: Update nmap/IPv6 information 0.26 2002-07-13/PB: Fill /proc-filesystem chapter, update DNS information about depricated A6/DNAME, change P-t-P tunnel setup to use of "ip" only 0.25.2 2002-07-11/PB: Minor spelling fixes 0.25.1 2002-06-23/PB: Minor spelling and other fixes 0.25 2002-05-16/PB: Cosmetic fix for 2\^{ }128, thanks to José Abílio Oliveira Matos for help with LyX 0.24 2002-05-02/PB: Add entries in URL list, minor spelling fixes 0.23 2002-03-27/PB: Add entries in URL list and at maillists, add a label and minor information about IPv6 on RHL 0.22 2002-03-04/PB: Add info about 6to4 support in kernel series 2.2.x and add an entry in URL list and at maillists 0.21 2002-02-26/PB: Migrate next grammar checks submitted by John Ronan 0.20.4 2002-02-21/PB: Migrate more grammar checks submitted by John Ronan, add some additional hints at DNS section 0.20.3 2002-02-12/PB: Migrate a minor grammar check patch submitted by John Ronan 0.20.2 2002-02-05/PB: Add mipl to maillist table 0.20.1 2002-01-31/PB: Add a hint how to generate 6to4 addresses 0.20 2002-01-30/PB: Add a hint about default route problem, some minor updates 0.19.2 2002-01-29/PB: Add many new URLs 0.19.1 2002-01-27/PB: Add some forgotten URLs 0.19 2002-01-25/PB: Add two German books, fix quote entinities in exported SGML code 0.18.2 2002-01-23/PB: Add a FAQ on the program chapter 0.18.1 2002-01-23/PB: Move "the end" to the end, add USAGI to maillists 0.18 2002-01-22/PB: Fix bugs in explanation of multicast address types 0.17.2 2002-01-22/PB: Cosmetic fix double existing text in history (at 0.16), move all credits to the end of the document 0.17.1 2002-01-20/PB: Add a reference, fix URL text in online-test-tools 0.17 2002-01-19/PB: Add some forgotten information and URLs about global IPv6 addresses 0.16 2002-01-19/PB: Minor fixes, remove "bold" and "emphasize" formats on code lines, fix "too long unwrapped code lines" using selfmade utility, extend list of URLs. 0.15 2002-01-15/PB: Fix bug in addresstype/anycast, move content related credits to end of document 0.14 2002-01-14/PB: Minor review at all, new chapter "debugging", review "addresses", spell checking, grammar checking (from beginning to 3.4.1) by Martin Krafft, add tcpdump examples, copy firewalling/netfilter6 from IPv6+Linux-HowTo, minor enhancements 0.13 2002-01-05/PB: Add example BIND9/host, move revision history to end of document, minor extensions 0.12 2002-01-03/PB: Merge review of David Ranch 0.11 2002-01-02/PB: Spell checking and merge review of Pekka Savola 0.10 2002-01-02/PB: First public release of chapter 1 Credits The quickest way to be added to this nice list is to send bug fixes, corrections, and/or updates to me ;-). If you want to do a major review, you can use the native LyX file (see original source) and send diffs against it, because diffs against SGML don't help too much. Major credits David Ranch <dranch at trinnet dot net>: For encouraging me to write this HOWTO, his editorial comments on the first few revisions, and his contributions to various IPv6 testing results on my IPv6 web site. Also for his major reviews and suggestions. Pekka Savola <pekkas at netcore dot fi>: For major reviews, input and suggestions. Martin F. Krafft <madduck at madduck dot net>: For grammar checks and general reviewing of the document. John Ronan <j0n at tssg dot wit dot ie>: For grammar checks. Georg Käfer <gkaefer at gmx dot at>: For detection of no proper PDF creation (fixed now by LDP maintainer Greg Ferguson), input for German books, big list of URLs, checking all URLs, many more suggestions, corrections and contributions, and the German translation Michel Boucey <mboucey at free dot fr>: Finding typos and some broken URLs, contribute some suggestions and URLs, and the French translation Other credits Document technique related Writing a LDP HOWTO as a newbie (in LyX and exporting this to DocBook to conform to SGML) isn't as easy as some people say. There are some strange pitfalls... Nevertheless, thanks to: Authors of the LDP Author Guide B. Guillon: For his DocBook with LyX HOWTO Content related credits Credits for fixes and hints are listed here, will grow sure in the future S .P. Meenakshi <meena at cs dot iitm dot ernet dot in>: For a hint using a "send mail" shell program on tcp_wrapper/hosts.deny Frank Dinies <FrankDinies at web dot de>: For a bugfix on IPv6 address explanation John Freed <jfreed at linux-mag dot com>: For finding a bug in IPv6 multicast address explanation Craig Rodrigues <crodrigu at bbn dot com>: For suggestion about RHL IPv6 setup Fyodor <fyodor at insecure dot org>: Note me about outdated nmap information Mauro Tortonesi <mauro at deepspace6 dot net>: For some suggestions Tom Goodale <goodale at aei-potsdam dot mpg dot de>: For some suggestions Martin Luemkemann <mluemkem at techfak dot uni-bielefeld dot de>: For a suggestion Jean-Marc V. Liotier <jim at jipo dot com>: Finding a bug Yaniv Kaul <ykaul at checkpoint dot com>: Finding a bug Arnout Engelen <arnouten at bzzt dot net>: For sending note about a draft was adopted to RFC now Stephane Bortzmeyer <bortzmeyer at nic dot fr>: Contributing persistent configuration on Debian lithis von saturnsys <lithis at saturnsys dot com>: Reporting a misaddressed URL Guy Hulbert <gwhulbert at rogers dot com>: Send a note that RFC1924 is probably an April fool's joke Tero Pelander <tpeland at tkukoulu dot fi>: Reporting a broken URL Walter Jontofsohn <wjontof at gmx dot de>: Hints for SuSE Linux 8.0/8.1 Benjamin Hofstetter <benjamin dot hofstetter at netlabs dot org>: Reporting a mispointing URL J.P. Larocque <piranha at ely dot ath dot cx>: Reporting archive URL for maillist users at ipv6 dot org Jorrit Kronjee <jorrit at wafel dot org>: Reporting broken URLs Colm MacCarthaigh <colm dot maccarthaigh at heanet dot ie>: Hint for sendfile issue on Apache2 The End Thanks for reading. Hope it helps! If you have any questions, subscribe to proper maillist and describe your problem providing as much as information as possible.