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Add more grammar checks and some hints about DNS 

Work-in-progress version 0.20.4
Modified Files:
	Linux+IPv6-HOWTO.lyx
This commit is contained in:
pbldp 2002-02-21 19:11:11 +00:00
parent 0895b501f0
commit b9ab9c84f0
1 changed files with 126 additions and 78 deletions
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LDP/users/Peter-Bieringer/Linux+IPv6-HOWTO.lyx
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@ -49,7 +49,7 @@ on>
<revhistory>
\layout SGML
<revision> <revnumber>Release 0.20.3</revnumber> <date>2002-02-12</date> <authorin
<revision> <revnumber>Release 0.20.4</revnumber> <date>2002-02-21</date> <authorin
itials>PB</authorinitials> <revremark>See
\begin_inset LatexCommand \ref[revision history]{revision-history}
@ -603,7 +603,7 @@ Link A link is a layer 2 network packet transport medium, examples are Ethernet,
Node A node is a host or a router.
\layout Description
Host Normally a single homed host on a link.
Host Generally a single homed host on a link.
Normally it has only one active network interface, e.g.
Ethernet or (not and) PPP.
\layout Description
@ -611,16 +611,16 @@ Host Normally a single homed host on a link.
Dual\SpecialChar ~
homed\SpecialChar ~
host A dual homed host is a node with two network (physical or
virtual) interfaces on two different links, but do not forwarding any packets
between the two connected links.
virtual) interfaces on two different links, but does not forward any packets
between the interfaces.
\layout Description
Router A router is a node with two or more network (physical or virtual)
interfaces, able to forward any packets between the interfaces.
interfaces, capable of forwarding packets between the interfaces.
\layout Description
Tunnel A tunnel is typically a point-to-point connection on which packets
are exchanged which contains data of another protocol, e.g.
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.
\layout Description
@ -633,7 +633,7 @@ Document related
Long code line wrapping signal char
\layout Standard
The special char
The special character
\begin_inset Quotes sld
\end_inset
@ -648,14 +648,15 @@ The special char
Placeholders
\layout Standard
In generic examples you will find sometimes like
In generic examples you will sometimes find the following:
\layout Code
<myipaddress>
\layout Standard
For real use on your system command line or in scripts this has to be replaced
with related content (also removing < and >), the result would be e.g.
with relevant content (removing the < and > of course), the result would
be e.g.
\layout Code
1.2.3.4
@ -664,13 +665,13 @@ For real use on your system command line or in scripts this has to be replaced
Commands in the shell
\layout Standard
Commands executable as non-root user starts with $, e.g.
Commands executable as non-root user begin with $, e.g.
\layout Code
$ whoami
\layout Standard
Commands executable as root user starts with #, e.g.
Commands executable as root user begin with #, e.g.
\layout Code
# whoami
@ -719,7 +720,7 @@ Experience with IPv4 configuration
\layout Standard
You should definitely have some experience in IPv4 configuration, otherwise
it's hard for you to understand what's really going on.
it will be hard for you to understand what is really going on.
\layout Subsubsection
Experience with the Domain Name System (DNS)
@ -741,14 +742,14 @@ tcpdump
\emph default
it can show you.
Otherwise, network debugging will very hard for you.
Otherwise, network debugging will very difficult for you.
\layout Subsection
Linux operating system compatible hardware
\layout Standard
Surely you want to run some tests too, not only read this HOWTO and fall
asleep here and there.
Surely you wish to experiment with real hardware, and not only read this
HOWTOto fall asleep here and there.
:)
\layout Chapter
@ -778,13 +779,13 @@ IPv6 is a new layer 3 transport protocol (see
\end_inset
from January 1980) and since its incantation, there were many requests
from January 1980) and since its inception, there have been many requests
for more addresses and enhanced capabilities.
Major changes in IPv6 are the redesign of the header, including the increase
of address size from 32 bits to 128 bits.
Because the 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.
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.
\layout Standard
For more information about the IPv6 history take a look at older IPv6 related
@ -865,8 +866,8 @@ The shown lines were copied from patch-2.1.8 (e-mail address was blanked on
In between
\layout Standard
Because of lack of manpower, the IPv6 implementation in the kernel couldn't
follow the discussed drafts or newly released RFCs.
Because of lack of manpower, the IPv6 implementation in the kernel wasunable
to follow the discussed drafts or newly released RFCs.
In October 2000, a project was started in Japan, called
\begin_inset LatexCommand \url[USAGI]{http://www.linux-ipv6.org/}
@ -879,7 +880,7 @@ Because of lack of manpower, the IPv6 implementation in the kernel couldn't
\end_inset
.
From time to time they created snapshot against current vanilla Linux kernel
From time to time they create snapshots against current vanilla Linux kernel
sources.
\layout Subsection
@ -891,10 +892,10 @@ Unfortunately, the
\end_inset
patch is so big, that current Linux networking maintainers aren't able
to include it in the production source of the Linux kernel 2.4.x series.
Therefore the 2.4.x series misses some (many) extensions and also didn't
fulfill all current drafts and RFCs.
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.
This can cause some interoperability problems with other operating systems.
\layout Subsection
@ -906,8 +907,8 @@ Future
\end_inset
now makes use of the new Linux kernel development series 2.5.x to put all
their current extensions into this development release.
is now making use of the new Linux kernel development series 2.5.x toinsert
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.
\layout Section
@ -915,8 +916,8 @@ Future
How do IPv6 addresses look like?
\layout Standard
\align left
As said, IPv6 addresses are 128 bits long.
This number of bits can cause very high decimal numbers with up to 39 digits:
As previously mentioned, IPv6 addresses are 128 bits long.
This number of bits generates very high decimal numbers with up to 39 digits:
\layout Code
@ -929,7 +930,7 @@ As said, IPv6 addresses are 128 bits long.
-1: 340282366920938463463374607431768211455
\layout Standard
\align left
"Such numbers are not really addresses that can be memorized.
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.
@ -941,8 +942,8 @@ nibble
\begin_inset Quotes srd
\end_inset
) are represented by a digit or char from 0-9 and a-f (10-15) and reduces
the length to 32 chars.
) are represented by a digit or character from 0-9 and a-f (10-15).
Thisformat reduces the length of the IPv6 address to 32 characters.
\layout Code
@ -954,7 +955,7 @@ nibble
-1: 0xffffffffffffffffffffffffffffffff
\layout Standard
\align left
This representation is also not very convenient (possible mix-up or loss
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 "
@ -1004,8 +1005,8 @@ One sequence of 16 bit blocks containing only zeroes can be replaced with
\end_inset
.
But not more than one time, because otherwise its no longer a unique representa
tion.
But not more than one at a time, otherwise it is no longer a unique representat
ion.
\layout Code
@ -1070,7 +1071,8 @@ On any IP header, the first 4 bits are reserved for protocol version.
) (which never really made it to the public)
\layout Standard
\align left
So the next free number was 6.
The next free number was 6.
Hence IPv6 was born!
\layout Subsection
IPv6 addresses: why such a high number of bits?
@ -1079,21 +1081,22 @@ 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 couple years.
However, 32 bits are not not enough to provide each network device with
a global address in the future.
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...
\layout Standard
\align left
So designers have chosen 128 bit, 4 times more in length and 2^96 in size
than in IPv4 today.
So designers have chosen 128 bits, 4 times more in length and 2^96 greater
in size than in IPv4 today.
\layout Standard
But the usable size is smaller than it may appear, because in the currently
defined address schema, 64 bits are user for interface identifiers.
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's still
Assuming the current strict levels of aggregation (/48, /35, ...), it is still
possible to
\begin_inset Quotes sld
\end_inset
@ -1102,28 +1105,29 @@ run out
\begin_inset Quotes srd
\end_inset
of space, but surely not in the near future.
of space, but hopefully not in the near future.
\layout Subsection
IPv6 addresses: why so small a number of bits on a new design?
\layout Standard
\align left
Well, there is one (or more?) people on the Internet who think about IPv8
and IPv16, but their design is far away from acceptance and implementation.
Well, there are (possibly) some people on the Internet who are thinking
about IPv8 and IPv16, but their design is far away from acceptance and
implementation.
\layout Standard
\align left
128 bit was the best choice regarding header overhead and data transport.
Think about the minimum Maximum Transfer Unit (MTU) in IPv4 (576 octets)
and in IPv6 (1280 octets), the header length in IPv4 is 20 octets (minimum,
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 nearly equal.
This means the header overhead is almost equal.
More bits for addresses would require bigger headers and therefore more
overhead.
Also think about the maximum MTU on normal links (like Ethernet today):
it's 1500 octets (in special cases: 9k octets using Jumbo frames).
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...
data in a Layer-3 packet were used for addresses and not for payload.
\layout Chapter
@ -1165,8 +1169,8 @@ Addresses without a special prefix
Localhost address
\layout Standard
This is a special address for the loopback interface, like IPv4 with its
This is a special address for the loopback interface, similiar to IPv4 with
its
\begin_inset Quotes sld
\end_inset
@ -1240,7 +1244,7 @@ IPv4-mapped IPv6 address
\layout Standard
IPv4-only IPv6-compatible addresses are sometimes used/shown for sockets
created by an IPv6-enabled daemon, but binding to an IPv4 address only.
created by an IPv6-enabled daemon, but only binding to an IPv4 address.
\layout Standard
These addresses are defined with a special prefix of length 96 (a.b.c.d is
@ -1265,7 +1269,7 @@ For example, the IPv4 address 1.2.3.4 looks like this:
IPv4-compatible IPv6 address
\layout Standard
Also for sockets, in this case it's for dual use and looking like
Also for sockets, in this case it is for a dual purpose and looks like:
\layout Code
0:0:0:0:0:0:a.b.c.d/96
@ -1277,7 +1281,8 @@ or in compressed format
::a.b.c.d/96
\layout Standard
They are also used by automatic tunneling, which is being replaced by
These addresses are also used by automatic tunneling, which is being replaced
by
\begin_inset LatexCommand \ref[6to4 tunneling]{tunneling-6to4}
\end_inset
@ -1288,7 +1293,8 @@ They are also used by automatic tunneling, which is being replaced by
Network part, also known as prefix
\layout Standard
Designers defined some address types and left a lot of room for future use.
Designers defined some address types and left a lot of scope for futuredefinitio
ns as currently unknown requirements arise.
\begin_inset LatexCommand \url[RFC 2373 [July 1998] / IP Version 6 Addressing Architecture]{http://rfc.net/rfc2373.html}
@ -1311,8 +1317,9 @@ Link local address type
\layout Standard
\align left
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 a router.
It's used for link communication like:
Using this address as destination the packet would never pass through a
router.
It's used for link communications such as:
\layout Itemize
\align left
anyone else here on this link?
@ -1322,7 +1329,7 @@ anyone here with a special address (e.g.
looking for a router)?
\layout Standard
\align left
They're starting with (
They begin with ( where
\emph on
\begin_inset Quotes sld
@ -1334,7 +1341,7 @@ x
\emph default
is any hex char, normally
is any hex character, normally
\emph on
\begin_inset Quotes sld
@ -1352,7 +1359,7 @@ x
fe8
\shape italic
\emph on
x: <- currently the only used one
x: <- currently the only one in use.
\layout Code
fe9
@ -1377,7 +1384,7 @@ An address with this prefix is found on each IPv6-enabled interface after
stateless auto-configuration (which is normally always the case).
\layout Standard
Note: only fe80 is currently used for that.
Note: only fe80 is currently in use.
\layout Subsection
Site local address type
@ -1403,7 +1410,7 @@ Another advantage: because it's possible to assign more than one address
in addition to a global one.
\layout Standard
\align left
It's starting with (
It begins with (
\emph on
\begin_inset Quotes sld
@ -1433,7 +1440,7 @@ x
fec
\shape italic
\emph on
x: <- common used one
x: <- most commonly used.
\layout Code
fed
@ -1470,7 +1477,7 @@ Today, there is one global address type defined (the first design, called
in older Linux kernel sources).
\layout Standard
\align left
It's starting with (
It begins with (
\emph on
x
\emph default
@ -1495,7 +1502,7 @@ xxx
:
\layout Standard
\align left
There are some subtypes defined by now:
There are some further subtypes defined, see below:
\layout Subsubsection
6bone test addresses
@ -1521,15 +1528,15 @@ A special 6bone test address which will be never be globally unique is starting
3ffe:ffff:
\layout Standard
and is mostly shown in examples, because if real addresses are shown, it's
possible that people do a copy & paste to their configuration files and
can cause duplicates an globally unique address.
This can cause many troubles on the original host (e.g.
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 an globally unique address.
This would cause serious problems for the original host (e.g.
getting answer packets for request that were never sent).
\newline
\newline
You can get perhaps still one of such prefix, see here
You can still apply for one of these prefixes, see here
\begin_inset LatexCommand \url[How to join 6bone]{http://www.6bone.net/6bone_hookup.html}
\end_inset
@ -6466,7 +6473,13 @@ A6, DNAME and reverse IP6.ARPA: specified in
\end_inset
, usable since BIND 9
, usable since BIND 9, but see also an information about the current state
at
\begin_inset LatexCommand \url[draft-ietf-dnsext-ipv6-addresses-00.txt]{http://www.ietf.org/internet-drafts/}
\end_inset
\layout Standard
Perhaps filled later more content, for the meantime take a look at given
@ -6493,6 +6506,31 @@ A6, DNAME and reverse IP6.ARPA: take a look into chapter 4 and 6 of the BIND
Because IP6.INT is deprecated (but still in use), a DNS server which will
support IPv6 information has to serve both reverse zones.
\layout Subsubsection
Current best practice
\layout Standard
Because there are some troubles around using the new formats, current best
practice is:
\layout Standard
Forward lookup support:
\layout Itemize
AAAA
\layout Itemize
A6 without chaining, means prefix length value set to 0
\layout Standard
Reverse lookup support:
\layout Itemize
Reverse nibble format for zone ip6.int
\layout Itemize
Reverse nibble format for zone ip6.arpa
\layout Subsection
Checking IPv6-enabled connect
@ -8868,11 +8906,21 @@ Revision history / Credits / The End
\end_inset
Revision history
\layout Standard
Versions x.y are published on the Internet.
\layout Standard
Versions x.y.z are work-in-progress and only published as LyX file on CVS.
\layout Subsection
Releases 0.x
\layout Description
0.20.4 2002-02-21/PB: Migrate more grammar checks submitted by John Ronan,
add some additional hints at DNS section
\layout Description
0.20.3 2002-02-12/PB: Migrate a minor grammar check patch submitted by John
Ronan
\layout Description