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Fixing "ethernet" which should be "Ethernet".

This commit is contained in:
mabrown 2003-04-24 23:58:04 +00:00
parent 6dac742743
commit 177919277b
12 changed files with 170 additions and 147 deletions
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24
LDP/guide/docbook/linux-ip/advanced-ip.xml
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@ -25,6 +25,14 @@
</section>
<section id="adv-proxy-arp">
<title>Breaking a network in two with proxy ARP</title>
<indexterm zone="adv-proxy-arp">
<primary>proxy ARP</primary>
<see>ARP, proxy</see>
</indexterm>
<indexterm zone="adv-proxy-arp">
<primary>ARP, proxy</primary>
<secondary>with <command>arp</command></secondary>
</indexterm>
<para>
Proxy ARP is a technique for splitting an IP network into two
separate segments. Hosts on one segment can only reach hosts in the
@ -36,7 +44,7 @@
</para>
<para>
Occasionally, this technique is incorrectly called proxy ARP bridging.
An ethernet bridge operates on frames and a router operates on packets.
An Ethernet bridge operates on frames and a router operates on packets.
The proxy ARP router should have routes to all hosts on both segments.
Once the router can reach all locally connected destinations via the
correct interfaces, you can begin to configure the proxy ARP
@ -65,7 +73,7 @@
subnet (maybe as small as a /30 network, with two usable IPs) makes an
excellent sequestered location for a host which requires more
protection or even, a generally untrusted host which shouldn't have
complete access to the ethernet to which the other machines connect.
complete access to the Ethernet to which the other machines connect.
</para>
<para>
For a practical example of this, see the relationship between the
@ -101,7 +109,7 @@
<listitem>
<para>
&masq-gw; replies that &isolde; should send packets for
192.168.100.1 to its ethernet address, 00:80:c8:f8:5c:71
192.168.100.1 to its Ethernet address, 00:80:c8:f8:5c:71
</para>
</listitem>
<listitem>
@ -118,7 +126,7 @@
<listitem>
<para>
&service-router; replies that &masq-gw; should send packets for
192.168.100.1 to its ethernet address, 00:c0:7b:7d:00:c8
192.168.100.1 to its Ethernet address, 00:c0:7b:7d:00:c8
</para>
</listitem>
<listitem>
@ -136,7 +144,7 @@
<listitem>
<para>
&masq-gw; replies that &service-router; should send packets for
192.168.100.17 to its ethernet address, 00:80:c8:f8:5c:74
192.168.100.17 to its Ethernet address, 00:80:c8:f8:5c:74
</para>
</listitem>
<listitem>
@ -153,7 +161,7 @@
<listitem>
<para>
&isolde; replies that &masq-gw; should send packets for
192.168.100.17 to its ethernet address, 00:80:c8:e8:4b:8e
192.168.100.17 to its Ethernet address, 00:80:c8:e8:4b:8e
</para>
</listitem>
<listitem>
@ -202,9 +210,9 @@
</para>
</section>
<section id="adv-multi-ethernet">
<title>Multiple connections to the same ethernet</title>
<title>Multiple connections to the same Ethernet</title>
<para>
Assume a machine has multiple connections to the same ethernet segment,
Assume a machine has multiple connections to the same Ethernet segment,
and has individual IPs bound to each interface. A peculiar feature of
linux is its willingness to respond to ARP requests for any IP bound
to any interface. This can lead to ARP flux, a situation where a

30
LDP/guide/docbook/linux-ip/basic.xml
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@ -230,7 +230,7 @@ Destination Gateway Genmask Flags Metric Ref Use Iface
</example>
<para>
For the moment, ignore the loopback interface (lo) and concentrate
on the ethernet interface. Examine the output of the
on the Ethernet interface. Examine the output of the
<command>ifconfig</command> command. We can learn a great deal about
the IP network to which we are connected simply by reading the
<command>ifconfig</command> output. For a thorough discussion of
@ -250,7 +250,7 @@ Destination Gateway Genmask Flags Metric Ref Use Iface
<para>
Because &tristan; will
advertise that it accepts packets with a destination address of
192.168.99.35, any frames (packets) appearing on the ethernet
192.168.99.35, any frames (packets) appearing on the Ethernet
bound for 192.168.99.35 will reach &tristan;. The process of
communicating the ownership of an IP address is called ARP. Read
<xref linkend="ether-arp-overview"/> for a complete discussion of
@ -282,11 +282,11 @@ Destination Gateway Genmask Flags Metric Ref Use Iface
and broadcasting as "chatty network traffic".
</para>
<para>
Broadcast techniques are used at the ethernet layer and the IP layer, so
the cautious person talks about ethernet broadcasts or IP broadcast.
Broadcast techniques are used at the Ethernet layer and the IP layer, so
the cautious person talks about Ethernet broadcasts or IP broadcast.
Refer to
<xref linkend="ether-arp-overview"/>, for more information on a common
use of broadcast ethernet frames.
use of broadcast Ethernet frames.
</para>
<para>
IP Broadcast techniques can be used to share information with all
@ -336,8 +336,8 @@ Destination Gateway Genmask Flags Metric Ref Use Iface
falls inside the address space 192.168.99.0/24. We also note that
the machine &tristan;
will route packets bound for 192.168.99.0/24 directly onto the
ethernet attached to eth0. This line in the routing table
identifies a network available on the ethernet attached to eth0
Ethernet attached to eth0. This line in the routing table
identifies a network available on the Ethernet attached to eth0
("Iface") by its network address ("Destination") and size ("Genmask").
</para>
<programlisting>
@ -430,7 +430,7 @@ round-trip min/avg/max/mdev = 0.238/0.238/0.238/0.000 ms</computeroutput>
id="ex-bpnl-tristan-out-text">
<simpara>
As the packet passes through the IP stack on &tristan;,
before hitting the ethernet, &tristan; adds its IP to the
before hitting the Ethernet, &tristan; adds its IP to the
list of IPs in the option field in the header.
</simpara>
</callout>
@ -528,7 +528,7 @@ round-trip min/avg/max/mdev = 0.238/0.238/0.238/0.000 ms</computeroutput>
</para>
<para>
The absence of a static route has caused two extra packets to be
generated on the ethernet for no benefit. Not only that, but
generated on the Ethernet for no benefit. Not only that, but
&tristan; will eventually expire the temporary route entry
<footnote>
<para>
@ -606,7 +606,7 @@ Destination Gateway Genmask Flags Metric Ref Use Iface
join the LAN.
</para>
<para>
Once the machine is booted and connected to the ethernet, it's
Once the machine is booted and connected to the Ethernet, it's
ready for IP reconfiguration. In order to join an
IP network, the following information is required. Refer to the
<link linkend="example-network-netmap">network map and
@ -757,7 +757,7 @@ Destination Gateway Genmask Flags Metric Ref Use Iface
interface after configuration to verify settings.
</para>
<example id="ex-basic-ifconfig-up">
<title>Bringing up an ethernet interface with <command>ifconfig</command></title>
<title>Bringing up an Ethernet interface with <command>ifconfig</command></title>
<programlisting>
<prompt>[root@morgan]# </prompt><userinput>ifconfig eth0 192.168.99.14 netmask 255.255.255.0 up</userinput>
<prompt>[root@morgan]# </prompt><userinput>ifconfig eth0</userinput>
@ -844,9 +844,9 @@ Destination Gateway Genmask Flags Metric Ref Use Iface
network, and the use of
<link linkend="tools-ifconfig"><command>ifconfig</command></link> and
<link linkend="tools-route"><command>route</command></link> it's
simple to readdress a machine on just about any ethernet you can
simple to readdress a machine on just about any Ethernet you can
attach to. The benefits of familiarity with these commands extend to
non-ethernet IP networks as well, because these commands operate on the
non-Ethernet IP networks as well, because these commands operate on the
IP layer, independent of the link layer.
</para>
</section>
@ -971,8 +971,8 @@ Destination Gateway Genmask Flags Metric Ref Use Iface
Communicate Using IP</title>
<listitem>
<para>
Each host must have a good connection to the ethernet. Verify a
good connection to the ethernet with <command>mii-tool</command>,
Each host must have a good connection to the Ethernet. Verify a
good connection to the Ethernet with <command>mii-tool</command>,
documented in
<xref linkend="tools-mii-tool"/>.
</para>

4
LDP/guide/docbook/linux-ip/bookinfo.xml
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@ -43,8 +43,8 @@
<para>
This guide provides an overview of many of the tools available
for IP network administration of the linux operating system,
kernels in the 2.2 and 2.4 series. It covers ethernet, ARP,
routing, NAT, and other topics central to the management of IP
kernels in the 2.2 and 2.4 series. It covers Ethernet, ARP,
IP routing, NAT, and other topics central to the management of IP
networks.
</para>
</abstract>

2
LDP/guide/docbook/linux-ip/bridging.xml
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@ -6,7 +6,7 @@
Bridging, once the realm of hardware devices, can also be performed by a
linux machine. Along with bridging comes the capability of filtering
and transforming frames (or even higher layer protocols) via hooks
at the ethernet layer with the <command>ebtables</command> and
at the Ethernet layer with the <command>ebtables</command> and
<command>iptables</command> commands.
</para>
<para>

88
LDP/guide/docbook/linux-ip/ether.xml
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@ -6,17 +6,17 @@
<primary>Ethernet</primary>
</indexterm>
<para>
The most common link layer network in use today is ethernet. Although
there are several common speeds of ethernet devices, they function
The most common link layer network in use today is Ethernet. Although
there are several common speeds of Ethernet devices, they function
identically with regard to higher layer protocols. As this documentation
focusses on higher layer protocols (IP), some fine distinctions about
different types of ethernet will be overlooked in favor of depicting the
uniform manner in which IP networks overlay ethernets.
different types of Ethernet will be overlooked in favor of depicting the
uniform manner in which IP networks overlay Ethernets.
</para>
<para>
Address Resolution Protocol provides the necessary mapping between link
layer
addresses and IP addresses for machines connected to ethernets. Linux
addresses and IP addresses for machines connected to Ethernets. Linux
offers control of ARP requests and replies via several
not-well-known <filename>/proc</filename> interfaces;
<filename>net/ipv4/conf/$DEV/proxy_arp</filename>,
@ -57,16 +57,16 @@
</para>
<para>
ARP defines the exchanges between network interfaces connected to an
ethernet media segment in order to map an IP address to a link layer
Ethernet media segment in order to map an IP address to a link layer
address on demand. Link layer addresses are hardware addresses (although
<link linkend="tools-ip-link-set-address">they are not immutable</link>)
on ethernet cards and IP addresses are logical addresses
assigned to machines attached to the ethernet. Subsequently in this
on Ethernet cards and IP addresses are logical addresses
assigned to machines attached to the Ethernet. Subsequently in this
chapter, link layer addresses may be known by many different names:
ethernet addresses, Media Access Control (MAC) addresses, and even
Ethernet addresses, Media Access Control (MAC) addresses, and even
hardware addresses.
Disputably, the correct term from the kernel's perspective is "link
layer address" because this address can be changed (on many ethernet
layer address" because this address can be changed (on many Ethernet
cards) via command line tools. Nevertheless, these terms are not
realistically distinct and can be used interchangeably.
</para>
@ -74,38 +74,38 @@
<title>Overview of Address Resolution Protocol</title>
<para>
Address Resolution Protocol (ARP) exists solely to glue together the
IP and ethernet networking layers. Since networking hardware
such as switches, hubs, and bridges operate on ethernet frames, they
IP and Ethernet networking layers. Since networking hardware
such as switches, hubs, and bridges operate on Ethernet frames, they
are unaware of the higher layer data carried by these frames
<footnote>
<para>
Some networking equipment vendors have built devices which are
sold as high performance switches and are capable of performing
operations on higher layer contents of ethernet frames.
operations on higher layer contents of Ethernet frames.
Typically, however, a switching device is not capable of
operating on IP packets.
</para>
</footnote>.
Similarly, IP layer devices, operating on IP packets need to be able
to transmit their IP data on ethernets. ARP defines the
to transmit their IP data on Ethernets. ARP defines the
conversation by which IP capable hosts can exchange mappings of
their ethernet and IP addressing.
their Ethernet and IP addressing.
</para>
<indexterm zone="ether-arp-request">
<primary>ARP request</primary>
</indexterm>
<anchor id="ether-arp-request"/>
<para>
ARP is used to locate the ethernet address associated with a desired IP
ARP is used to locate the Ethernet address associated with a desired IP
address. When a machine has a packet bound for another IP on a locally
connected ethernet network, it will send a broadcast ethernet frame
containing an ARP request onto the ethernet. All machines with the same
ethernet broadcast address will receive this packet
connected Ethernet network, it will send a broadcast Ethernet frame
containing an ARP request onto the Ethernet. All machines with the same
Ethernet broadcast address will receive this packet
<footnote>
<para>
The kernel uses the ethernet broadcast address configured on the
The kernel uses the Ethernet broadcast address configured on the
link layer device. This is rarely anything but ff:ff:ff:ff:ff:ff.
In the extraordinary event that this is not the ethernet broadcast
In the extraordinary event that this is not the Ethernet broadcast
address in your network, see
<xref linkend="tools-ip-link-set-address"/>.
</para>
@ -136,7 +136,7 @@
<para>
In <xref linkend="ex-basic-ping"/>, we used <command>ping</command> to
test reachability of &masq-gw;. Using a packet sniffer to capture
the sequence of packets on the ethernet as a result of &tristan;'s
the sequence of packets on the Ethernet as a result of &tristan;'s
attempt to ping, provides an example of ARP <foreignphrase>in flagrante
delicto</foreignphrase>. Consult the
<link linkend="example-network-netmap">example network map</link> for a
@ -146,7 +146,7 @@
<para>
This is an archetypal conversation between two
computers exchanging relevant hardware addressing in order that they
can pass IP packets, and is comprised of two ethernet frames.
can pass IP packets, and is comprised of two Ethernet frames.
</para>
<indexterm zone="ex-ether-arp-overview">
<primary><command>arping</command></primary>
@ -179,8 +179,8 @@
<primary>ARP request</primary>
</indexterm>
<simpara>
This broadcast ethernet frame, identifiable by the
destination ethernet address with all bits set
This broadcast Ethernet frame, identifiable by the
destination Ethernet address with all bits set
(ff:ff:ff:ff:ff:ff) contains an ARP request from &tristan;
for IP address 192.168.99.254. The request includes the
source link layer address and the IP address of
@ -204,7 +204,7 @@
<simpara>
The machine which initiated the ARP request (&tristan;)
now has enough information to encapsulate an IP packet in
an ethernet frame and forward it to the link layer address
an Ethernet frame and forward it to the link layer address
of the recipient (00:80:c8:f8:5c:73).
</simpara>
</callout>
@ -223,8 +223,8 @@
</calloutlist>
</example>
<para>
This example is the commonest example of ARP traffic on an ethernet.
In summary, an ARP request is transmitted in a broadcast ethernet
This example is the commonest example of ARP traffic on an Ethernet.
In summary, an ARP request is transmitted in a broadcast Ethernet
frame. The ARP reply is a unicast response, containing the desired
information, sent to the requestor's link layer address.
</para>
@ -296,7 +296,7 @@
</programlisting>
</example>
<para>
These two uses of <command>arping</command> can help diagnose ethernet
These two uses of <command>arping</command> can help diagnose Ethernet
and ARP problems--particularly hosts replying for addresses which do
not belong to them.
</para>
@ -336,7 +336,7 @@ Received 1 response(s)
<para>
Address Resolution Protocol, which provides a method to connect
physical network addresses with logical network addresses
is a key element to the deployment of IP on ethernet networks.
is a key element to the deployment of IP on Ethernet networks.
</para>
</section>
<section id="ether-arp-cache">
@ -406,7 +406,7 @@ Received 1 response(s)
expiration of entries in the ARP cache.
</para>
<para>
When a host is down or disconnected from the ethernet, there is a
When a host is down or disconnected from the Ethernet, there is a
period of time during which other hosts may have an ARP cache entry
for the disconnected host. Any other machine may display a neighbor
table with the link layer address of the recently disconnected host.
@ -513,7 +513,7 @@ Received 1 response(s)
<simpara>
Before the entry has expired for 192.168.99.7, but after the
host has been disconnected from the network. During this
time, &tristan; will continue to send out ethernet frames with
time, &tristan; will continue to send out Ethernet frames with
the destination frame address set to the link layer address
according to this entry.
</simpara>
@ -597,9 +597,9 @@ Received 1 response(s)
<para>
Complete ARP suppression is not difficult at all. ARP suppression can
be accomplished under linux on a per-interface basis by setting the
noarp flag on any ethernet interface.
noarp flag on any Ethernet interface.
Disabling ARP will require static neighbor table mappings
for all hosts wishing to exchange packets across the ethernet.
for all hosts wishing to exchange packets across the Ethernet.
</para>
<para>
To suppress ARP on an interface simply use <command>ip
@ -627,7 +627,7 @@ Received 1 response(s)
When a linux box is connected to a network segment with multiple
network cards, a potential problem with the link layer address
to IP address mapping can occur.
The machine may respond to ARP requests from both ethernet interfaces.
The machine may respond to ARP requests from both Ethernet interfaces.
On the machine creating the ARP request, these multiple answers can
cause confusion, or worse yet, non-deterministic population
of the ARP cache. Known as ARP flux
@ -645,7 +645,7 @@ Received 1 response(s)
</para>
<para>
This is a simple illustration of the problem in a network where a
server has two ethernet adapters connected to the same media
server has two Ethernet adapters connected to the same media
segment. They need not have IP addresses in the same IP network for
the ARP reply to be generated by each interface. Note the first
two replies received in response to the ARP broadcast request.
@ -710,12 +710,12 @@ Received 4 response(s)</computeroutput>
determine the interface through which to send the
reply, instead of the default behaviour
(<link linkend="ex-ether-arp-flux">shown above</link>), replying
from all ethernet interfaces which receive the request.
from all Ethernet interfaces which receive the request.
</para>
<!--
FIXME; read the spec, why is this smart? Doesn't this mean
using the informational data in the ethernet frame?
using the informational data in the Ethernet frame?
-->
<para>
@ -963,7 +963,7 @@ Received 2 response(s)</computeroutput>
</indexterm>
<indexterm zone="ether-arp-proxy-mediumid">
<primary><constant>ARP, proxy</constant></primary>
<secondary>with kernel <constant>medium_id</constant></secondary>
<secondary>with kernel</secondary>
<tertiary><constant>medium_id</constant></tertiary>
</indexterm>
<para>
@ -1031,7 +1031,7 @@ ALTER := [ src IP ] [ llsrc LLADDR ] [ lldst LLADDR ]</computeroutput>
</section>
</section>
<section id="ether-vlan">
<title>Connecting to an ethernet 802.1q VLAN</title>
<title>Connecting to an Ethernet 802.1q VLAN</title>
<indexterm zone="ether-vlan">
<primary>VLAN</primary>
</indexterm>
@ -1039,7 +1039,7 @@ ALTER := [ src IP ] [ llsrc LLADDR ] [ lldst LLADDR ]</computeroutput>
Virtual LANs are a way to take a single switch and subdivide it into
logical media segments. A single switch port in a VLAN-capable switch
can carry packets from multiple virtual LANs and linux can understand
the format of these ethernet frames. For more on this, see
the format of these Ethernet frames. For more on this, see
<ulink url="http://www.candelatech.com/~greear/vlan.html">the linux
802.1q VLAN implementation site</ulink>.
</para>
@ -1054,8 +1054,8 @@ ALTER := [ src IP ] [ llsrc LLADDR ] [ lldst LLADDR ]</computeroutput>
support under linux. Ben McKeegan wrote a
<ulink url="http://www.wanfear.com/pipermail/vlan/2002q4/002882.html">good
summary</ulink> of the MTU/MRU issues involved with VLANs and 10/100
Ethernet. Gigabit ethernet drivers are not hamstrung with this problem.
Consider using gigabit ethernet cards from the outset to avoid these
Ethernet. Gigabit Ethernet drivers are not hamstrung with this problem.
Consider using gigabit Ethernet cards from the outset to avoid these
potential problems.
</para>
<example id="ex-ether-vlan">
@ -1231,7 +1231,7 @@ The interface eth3 is up, shutting it down it to enslave it.</computeroutput>
Immediately noticeable, there is a new flag in the <command>ip link
show</command> output. The <constant>MASTER</constant> and
<constant>SLAVE</constant> flags clearly report the nature of the
relationship between the interfaces. Also, the ethernet interfaces
relationship between the interfaces. Also, the Ethernet interfaces
indicate the master interface via the keywords <constant>master
bond0</constant>.
</para>

6
LDP/guide/docbook/linux-ip/example-network.xml
View File

@ -161,19 +161,19 @@
</row>
<row>
<entry>&isdn-router;</entry>
<entry>(ethernet)</entry>
<entry>(Ethernet)</entry>
<entry>192.168.99.1/24</entry>
<entry>00:c0:7b:45:6a:39</entry>
</row>
<row>
<entry>&branch-router;</entry>
<entry>(ethernet)</entry>
<entry>(Ethernet)</entry>
<entry>192.168.98.254/24</entry>
<entry>00:c0:7b:37:af:91</entry>
</row>
<row>
<entry>&service-router;</entry>
<entry>(ethernet)</entry>
<entry>(Ethernet)</entry>
<entry>192.168.100.1/24</entry>
<entry>00:c0:7b:7d:00:c8</entry>
</row>

6
LDP/guide/docbook/linux-ip/intro.xml
View File

@ -30,7 +30,7 @@
Second, I assume the reader is comfortable with command line tools
and the Linux, Unix, or BSD environments. Finally, I assume the
reader has working
network cards and a Linux OS. For assistance with ethernet cards, the
network cards and a Linux OS. For assistance with Ethernet cards, the
there exists a good
<ulink url="http://www.tldp.org/HOWTO/Ethernet-HOWTO.html">Ethernet
HOWTO</ulink>.
@ -46,8 +46,8 @@
</para>
<para>
This guide has been written primarily as a companion reference to IP
networking on ethernets. Although I do allude to other link layer types
occasionally in this book, the focus has been IP as used in ethernet.
networking on Ethernets. Although I do allude to other link layer types
occasionally in this book, the focus has been IP as used in Ethernet.
Ethernet is one of the most common networking devices supported under
linux, and is practically ubiquitous.
</para>

26
LDP/guide/docbook/linux-ip/links.xml
View File

@ -118,7 +118,7 @@
<listitem>
<para>
Address Resolution Protocol is used to provide the glue between
ethernet link layer information (hardware addresses) and the IP
Ethernet link layer information (hardware addresses) and the IP
layer. This
<ulink url="http://www.erg.abdn.ac.uk/users/gorry/course/inet-pages/arp.html">page</ulink>
is instructive in ARP.
@ -356,6 +356,24 @@
</listitem>
</itemizedlist>
</section>
<section id="links-ipfwadm">
<title><command>ipfwadm</command> Resources</title>
<itemizedlist>
<listitem>
<para>
Not covered in this documentation, <command>ipfwadm</command> is
only supported in the linux 2.2 and 2.4 kernels via backward
compatible interfaces to the internal packet filtering
architectures. Read more on <command>ipfwadm</command>
<ulink url="http://www.xos.nl/linux/ipfwadm/paper/">here</ulink>.
</para>
</listitem>
<listitem>
<para>
</para>
</listitem>
</itemizedlist>
</section>
<section id="links-systems">
<title>General Systems References</title>
<itemizedlist>
@ -372,7 +390,7 @@
For a description of the
<ulink url="http://www.gnumonks.org/ftp/pub/doc/packet-journey-2.4.html">path
a frame on the wire takes</ulink> through the kernel from
the ethernet through to the upper layers, Harald Welte's
the Ethernet through to the upper layers, Harald Welte's
brief proves instructive.
</para>
</listitem>
@ -587,7 +605,7 @@
<listitem>
<para>
The 2.2 and 2.4 series support bonding of interfaces which allows
both link aggregation (IEEE 802.3ad) and failover use of ethernet
both link aggregation (IEEE 802.3ad) and failover use of Ethernet
interfaces. The canonical source for documentation about bonding
is <filename>Documentation/networking/bonding.txt</filename> in
the kernel source distribution.
@ -669,7 +687,7 @@
<para>
The <ulink url="http://www.tazenda.demon.co.uk/phil/net-tools/">net-tools</ulink>
package is a collection of basic utilities for managing the
ethernet and IP layer under linux.
Ethernet and IP layer under linux.
</para>
</listitem>
<listitem>

10
LDP/guide/docbook/linux-ip/tools-diagnostics.xml
View File

@ -4,7 +4,7 @@
<title>Diagnostics</title>
<para>
Now that we have covered most of the basic tools for management of
routes, IP addresses, and a few ethernet tools, we come to a set of
routes, IP addresses, and a few Ethernet tools, we come to a set of
tools which are used primarily to help you figure out what is wrong in
your network, where a route is broken, or even, simply, whether a host
is reachable.
@ -175,7 +175,7 @@ round-trip min/avg/max/mdev = 0.179/0.208/0.231/0.024 ms</computeroutput>
As with much data collection, you need a large sample set of data to
draw conclusions about your network. You can usually conclude that
something is quite wrong if you cannot reach a remote host, but you
should be cautious when concluding that your ethernet card is bad
should be cautious when concluding that your Ethernet card is bad
simply because round-trip times to a destination on the LAN is high.
It is more likely that there's another problem. Collecting
<command>ping</command> data from a number of hosts to a number of
@ -280,7 +280,7 @@ round-trip min/avg/max/mdev = 37.840/62.234/97.807/12.946 ms</computeroutput>
packet loss. By increasing the packet size of the packet we are
sending across the link we can get a sense for how quickly
performance degrades on this link. If we use a much larger packet
size (still smaller than ethernet's 1500 byte frame), we see even
size (still smaller than Ethernet's 1500 byte frame), we see even
more packet loss. We'll specify a packet size of 512 bytes with the
<option>-s</option> option.
</para>
@ -369,7 +369,7 @@ round-trip min/avg/max/mdev = 47.893/52.102/56.311/4.209 ms</computeroutput>
in smaller networks.
</para>
<para>
The first IP we hit is our own IP on the way out our ethernet
The first IP we hit is our own IP on the way out our Ethernet
interface, 192.168.98.82. Then it is a palindromic journey through
the network stacks of each of the following hosts in order:
&branch-router;, &isdn-router;, &tristan;, and back again
@ -808,7 +808,7 @@ tcp 0 0 192.168.98.82:44320 192.168.100:netbios-ssn TIME_WAIT</c
</para>
<para>
The first line describes a TCP connection to the IP locally hosted
on &morgan;'s ethernet interface. The connection was initiated from
on &morgan;'s Ethernet interface. The connection was initiated from
an ephemeral port (40991) on &tristan; to a service running on port
22. The service normally running on this well-known port is sshd,
so we can conclude that somebody on &tristan; has connected to the

93
LDP/guide/docbook/linux-ip/tools-ethernet.xml
View File

@ -4,29 +4,29 @@
<title>Ethernet Layer Tools</title>
<para>
The section here will cover tools which manipulate, display
characteristics of or probe ethernet devices. Because ethernet is one
characteristics of or probe Ethernet devices. Because Ethernet is one
of the most available and widely spread networking media in use today,
we'll concentrate on ethernet rather than other link layer protocols.
we'll concentrate on Ethernet rather than other link layer protocols.
</para>
<para>
As with any networking stack, the lower layers must be functioning
properly in order for the higher layer protocols to operate. The tools
covered in this section will provide the resources you need to verify
the proper operation of your linux machine in an ethernet environment.
the proper operation of your linux machine in an Ethernet environment.
</para>
<para>
You probably knew before reading this that you can look at the link
light on your ethernet switch/hub and the link light on your ethernet
light on your Ethernet switch/hub and the link light on your Ethernet
card to verify a good connection. Now you can use
<link linkend="tools-mii-tool"><command>mii-tool</command></link> to
ask the ethernet driver if it agrees. Once you have verified a good media
ask the Ethernet driver if it agrees. Once you have verified a good media
connection, you may want to set other link layer characteristics on your
ethernet device. For this,
Ethernet device. For this,
<link linkend="tools-ip-link"><command>ip link</command></link> is
the perfect tool.
</para>
<para>
To see if anybody is using an IP address already on the ethernet to
To see if anybody is using an IP address already on the Ethernet to
which you are connecting, you can use
<link linkend="tools-arping"><command>arping</command></link>
and if you want to play with the arp tables, the
@ -69,7 +69,7 @@
<para>
The MAC address in the third column is always a six part hexadecimal
number. In practice, the MAC address (also known as the hardware
address or the ethernet address) is not normally needed for the
address or the Ethernet address) is not normally needed for the
majority of troubleshooting problems, however knowing how to retrieve
the MAC address can help when tracking down problems in a network
<footnote>
@ -78,12 +78,12 @@
to join the network were suddenly and apparently inexplicably
receiving addresses in an unexpected netblock.
After some head-scratching and judicious use of
<command>tcpdump</command> to record the ethernet address of the
<command>tcpdump</command> to record the Ethernet address of the
DHCP server giving out the bogus IP information, the administrator
was able to track down a device through the switch to a port on
the LAN.
It turned out to be a tiny (4-port) hub with an embedded DHCP server
which was intended for home use! The knowledge of the ethernet
which was intended for home use! The knowledge of the Ethernet
address of the rogue DHCP server was the key to physically
locating the device.
</para>
@ -119,7 +119,7 @@
respond for ARP requests on eth3 for the IP 192.168.100.17. If the
<systemitem class="systemname">service-router</systemitem> has a
packet bound for 192.168.100.17, it will generate an ARP request to
which we will respond with the ethernet address of our eth3 interface.
which we will respond with the Ethernet address of our eth3 interface.
</para>
<para>
Moments after you have added this arp table entry, you realize that
@ -160,19 +160,19 @@
An almost unknown command (mostly because it is not frequently
necessary), the <command>arping</command> utility performs an action
similar to <link linkend="tools-ping"><command>ping</command></link>,
but at the ethernet layer. Where <command>ping</command> tests the
but at the Ethernet layer. Where <command>ping</command> tests the
reachability of an IP address, <command>arping</command> reports the
reachability and round-trip time of an IP address hosted on the local
network.
</para>
<para>
There are several modes of operation for this utility. Under normal
operation, <command>arping</command> displays the ethernet and IP
operation, <command>arping</command> displays the Ethernet and IP
address of the target as well as the time elapsed between the
arp request and the arp reply.
</para>
<example id="ex-tools-arping-listing">
<title>Displaying reachability of an IP on the local ethernet with <command>arping</command></title>
<title>Displaying reachability of an IP on the local Ethernet with <command>arping</command></title>
<programlisting>
<prompt>[root@masq-gw]# </prompt><userinput>arping -I eth0 -c 2 192.168.100.17</userinput>
<computeroutput>ARPING 192.168.100.17 from 192.168.100.254 eth0
@ -189,13 +189,13 @@ Received 2 response(s)</computeroutput>
<command>-A</command> option. A kernel with support for <link
linkend="adv-non-local-bind">non-local bind</link> can be used with
arping for the nefarious purpose of wreaking havoc on
an otherwise properly configured ethernet. By performing gratuitous arp
an otherwise properly configured Ethernet. By performing gratuitous arp
and broadcasting incorrect arp information, arp tables in poorly
designed IP stacks can become quite confused.
</para>
<para>
<command>arping</command> can detect if an IP address is
currently in use on an ethernet. Called duplicate address detection,
currently in use on an Ethernet. Called duplicate address detection,
this use of <command>arping</command> is increasingly common in
networking scripts.
</para>
@ -227,13 +227,13 @@ Received 2 response(s)</computeroutput>
address is in use by
<systemitem class="systemname">tristan</systemitem>,
<systemitem class="systemname">dietrich</systemitem> receives a
response. Any response by a device on the ethernet indicating that an
response. Any response by a device on the Ethernet indicating that an
IP address is in use will cause the <command>arping</command> command
to exit with a non-zero exit code (specifically, exit code 1).
</para>
<para>
Note, that the ethernet device must already be in an UP state (see
<xref linkend="tools-ip-link"/>). If the ethernet device has not been
Note, that the Ethernet device must already be in an UP state (see
<xref linkend="tools-ip-link"/>). If the Ethernet device has not been
brought up, the <command>arping</command> utility will exit with a
non-zero exit code (specifically, exit code 2).
</para>
@ -251,7 +251,7 @@ Received 2 response(s)</computeroutput>
flags</link>, <link linkend="tools-ip-link-set-mtu">change MTU</link>,
<link linkend="tools-ip-link-set-name">the name of the interface</link>,
and even the <link linkend="tools-ip-link-set-address">hardware and
ethernet broadcast address</link>.
Ethernet broadcast address</link>.
</para>
<para>
The <command>ip link</command> tool provides the following two verbs:
@ -314,8 +314,8 @@ Received 2 response(s)</computeroutput>
(MTU)</link> the active queueing mechanism (if any), and
the queue size if there is a queue present. The second line will
always indicate the type of link layer in use on the device, and
link layer specific information. For ethernet, the common case,
the current hardware address and ethernet broadcast address will be
link layer specific information. For Ethernet, the common case,
the current hardware address and Ethernet broadcast address will be
displayed.
</para>
</section>
@ -331,7 +331,7 @@ Received 2 response(s)</computeroutput>
I have not found need to use the <command>ip link
set</command> command with any of the toggle flags Regardless,
here's an example of the proper operation of the utility. Paranoid
network administrators or those who wish to map ethernet addresses
network administrators or those who wish to map Ethernet addresses
manually should take special note of the <command>ip link set arp
off</command> command.
</para>
@ -577,12 +577,12 @@ default via 192.168.99.254 dev eth0</computeroutput>
</para>
</section>
<section id="tools-ip-link-set-address">
<title>Changing hardware or ethernet broadcast address with
<title>Changing hardware or Ethernet broadcast address with
<command>ip link set</command></title>
<para>
This command changes the hardware or broadcast address of a device
as used on the media to which it is connected. Supposedly there can
be name clashes between two different ethernet cards sharing the
be name clashes between two different Ethernet cards sharing the
same hardware address. I have yet to see this problem, so I suspect
that changing the hardware address is more commonly used in
vulnerabliity testing or even more nefarious purposes.
@ -591,10 +591,10 @@ default via 192.168.99.254 dev eth0</computeroutput>
Alternatively, one can set the broadcast address to a different
value, which as Alexey remarks as an aside in the
&iproute2; manual will "break networking."
Changing the ethernet broadcast address implies that no
Changing the Ethernet broadcast address implies that no
conventionally configured host will answer broadcast ARP frames
transmitted onto the ethernet. Since conventional ARP requests
are sent to the ethernet broadcast of
transmitted onto the Ethernet. Since conventional ARP requests
are sent to the Ethernet broadcast of
<constant>ff:ff:ff:ff:ff:ff</constant>, broadcast frames sent after
changing the link layer broadcast address will not be received by
other hosts on the segment. To echo
@ -629,7 +629,7 @@ default via 192.168.99.254 dev eth0</computeroutput>
</para>
<para>
Note, however, in the tcpdump output, the effect of changing
the ethernet broadcast address. As discussed in the paragraph
the Ethernet broadcast address. As discussed in the paragraph
above, changing the broadcast is probably not a good idea
<footnote>
<para>
@ -638,9 +638,6 @@ default via 192.168.99.254 dev eth0</computeroutput>
</para>
</footnote>.
</para>
</section>
<section id="tools-ip-link-conclusion">
<title></title>
<para>
As you can see, the <command>ip link</command> utility is a treasure
trove of information and allows a great deal of control over the
@ -760,7 +757,7 @@ default via 192.168.99.254 dev eth0</computeroutput>
<para>
This creates an entry in the neighbor table which maps
192.168.100.1 to link layer address 00:c0:7b:7d:00:c8. Subsequent IP
packets bound for 192.168.100.1 will be encapsulated in ethernet
packets bound for 192.168.100.1 will be encapsulated in Ethernet
frames with 00:c0:7b:7d:00:c8 in the destination bytes. This
permanent mapping cannot be overridden by ARP. It would need to be
removed with
@ -857,9 +854,9 @@ default via 192.168.99.254 dev eth0</computeroutput>
<section id="tools-mii-tool">
<title><command>mii-tool</command></title>
<para>
A key tool for determining if you are connected to the ethernet, and
A key tool for determining if you are connected to the Ethernet, and
if so, at what speed. The <command>mii-tool</command> program
does not support all ethernet devices, as some ethernet devices have
does not support all Ethernet devices, as some Ethernet devices have
their own vendor-supplied tools to report the same information. The
<command>mii-tool</command> source code is based on a tool called
<command>mii-diag</command> which provides slightly more information
@ -871,14 +868,14 @@ default via 192.168.99.254 dev eth0</computeroutput>
you'll encounter in output from <command>mii-tool</command>
<footnote>
<para>
There is a standard speed/ethernet transmission style supported by
There is a standard speed/Ethernet transmission style supported by
<command>mii-tool</command> to which I have not referred. That is
100BaseT4. 100BaseT4 provides support for 100 megabit ethernet
100BaseT4. 100BaseT4 provides support for 100 megabit Ethernet
networking over Category 3 rated cable. This is probably not a
concern for most recently upgraded network infrastructure. The
standard networking cable pulled in new construction and
renovation is now Category 5 cable which supports 100Base-Tx-FD
and possibly gigabit ethernet. So, let's relegate 100BaseT4 to
and possibly gigabit Ethernet. So, let's relegate 100BaseT4 to
this footnote, and resume.
</para>
</footnote>.
@ -914,7 +911,7 @@ default via 192.168.99.254 dev eth0</computeroutput>
</table>
<para>
The raw number indicates the number of bits which can be exchanged
between two ethernet devices over the wire. So 10 megabit ethernet
between two Ethernet devices over the wire. So 10 megabit Ethernet
can support the transmission of ten million bits per second. The
suffix to each identifier indicates whether both hosts can send and
receive simultaneously or not. Half duplex means that each device can
@ -923,7 +920,7 @@ default via 192.168.99.254 dev eth0</computeroutput>
</para>
<para>
The simplest use of <command>mii-tool</command> reports the link
status of all ethernet devices on a system. Any argument
status of all Ethernet devices on a system. Any argument
to <command>mii-tool</command> is interpreted as an interface name to
query for link status.
</para>
@ -945,22 +942,22 @@ default via 192.168.99.254 dev eth0</computeroutput>
<para>
In the above example, we can infer that
<systemitem class="systemname">tristan</systemitem> has only one
ethernet device (or no ethernet drivers loaded for any other present
ethernet devices). The first ethernet device has successfully
Ethernet device (or no Ethernet drivers loaded for any other present
Ethernet devices). The first Ethernet device has successfully
negotiated a 100 megabit full duplex connection with the device to
which it is connected.
</para>
<para>
Although a great rarity, you may have occasion to dictate to the
ethernet interface the speed at which it should talk to the switch or
Ethernet interface the speed at which it should talk to the switch or
hub. <command>mii-tool</command> supports a mode of operation under
which you indicate supported modes for autonegotiation. Normally, two
connected devices will negotiate the fastest possible commonly shared
speed. You can select what speeds you want to support on an ethernet
speed. You can select what speeds you want to support on an Ethernet
interface by using <command>mii-tool</command>.
</para>
<example id="tools-mii-tool-advertise">
<title>Specifying ethernet port speeds with <command>mii-tool --advertise</command></title>
<title>Specifying Ethernet port speeds with <command>mii-tool --advertise</command></title>
<programlisting>
<prompt>[root@tristan]# </prompt><userinput>mii-tool mii-tool --advertise 10baseT-HD,10baseT-FD</userinput>
<computeroutput>restarting autonegotiation...</computeroutput>
@ -970,12 +967,12 @@ default via 192.168.99.254 dev eth0</computeroutput>
</example>
<para>
After we specified that we wished only to support 10baseT-HD and
10baseT-FD as acceptable speeds, mii-tool caused the ethernet driver
10baseT-FD as acceptable speeds, mii-tool caused the Ethernet driver
to renegotiate port speed with the attached device. Here we selected
10baseT-FD.
</para>
<example id="tools-mii-tool-force">
<title>Forcing ethernet port speed with <command>mii-tool --force</command></title>
<title>Forcing Ethernet port speed with <command>mii-tool --force</command></title>
<programlisting>
<prompt>[root@tristan]# </prompt><userinput>mii-tool --force 10baseT-FD</userinput>
<prompt>[root@tristan]# </prompt><userinput>mii-tool</userinput>
@ -987,7 +984,7 @@ default via 192.168.99.254 dev eth0</computeroutput>
</programlisting>
</example>
<para>
After manipulating the speed at which the ethernet driver would
After manipulating the speed at which the Ethernet driver would
communicate with the connected device on &tristan;, we chose to
restart the autonegotiation process without forcing a particular speed
or advertising a particular speed.

16
LDP/guide/docbook/linux-ip/tools-ip-management.xml
View File

@ -63,7 +63,7 @@
<command>ifconfig</command></title>
<para>
In its simplest use, <command>ifconfig</command> merely reports the
IP interface and relevant statistics. For ethernet devices, the
IP interface and relevant statistics. For Ethernet devices, the
hardware address, IP address, broadcast, netmask, IP interface states,
and some other additional information is presented. For other
interfaces, different information may be presented to the user, but
@ -139,7 +139,7 @@ lo Link encap:Local Loopback
</example>
<para>
Naturally, when we view the active interfaces after downing the first
ethernet interface, we see that eth0 is no longer present. This is
Ethernet interface, we see that eth0 is no longer present. This is
exactly what we had intended. Now to bring up the interface, we'll
need the IP address and netmask information.
</para>
@ -191,12 +191,12 @@ lo Link encap:Local Loopback
</para>
<para>
The first line of each interface definition represents data which
cannot be altered with ifconfig. If we consider only ethernet
cannot be altered with ifconfig. If we consider only Ethernet
interfaces, the link encapsulation will always say "Ethernet", and the
hardware address cannot be altered with <command>ifconfig</command>
<footnote>
<para>
If you need to change the hardware address of an ethernet
If you need to change the hardware address of an Ethernet
interface, you have a strange need, but you can accomplish this
using the <link linkend="tools-ip-link-set-address"><command>ip
link set address</command></link> command.
@ -209,12 +209,12 @@ lo Link encap:Local Loopback
The third line indicates the current states of the interface, maximum
transmission unit, and the metric for this interface. Possible
state options are itemized in the table below. The maximimum
transmission unit is routinely set to 1500 bytes for ethernet and
transmission unit is routinely set to 1500 bytes for Ethernet and
promptly forgotten. MTU suddenly becomes important when IP packets
are forwarded across a link layer which requires a smaller MTU. Thus
<command>ifconfig</command> provides a method to set the MTU on an
interface. For more on MTU, see <xref linkend="routing-icmp-mtu"/>. The
remaining lines of output are taken from the ethernet driver. See
remaining lines of output are taken from the Ethernet driver. See
further discussion of these statistics below.
</para>
</section>
@ -407,13 +407,13 @@ lo Link encap:Local Loopback
<para>
The final fields in the first line of output for each device entry
refer to the traffic control queueing discipline (qdisc) and the
ethernet buffer transmit queue length (qlen). For more on
Ethernet buffer transmit queue length (qlen). For more on
understanding and using traffic control under linux, see
<ulink url="http://lartc.org/howto/">the LARTC documentation</ulink>.
</para>
<para>
The second line of output describes the link layer characteristics
of the device. For ethernet devices, this will always say
of the device. For Ethernet devices, this will always say
"link/ether" followed by the hardware address of the device and the
media broadcast address. For more detail on the link layer
characteristics of a device see <xref linkend="tools-ip-link"/>.

12
LDP/guide/docbook/linux-ip/tools-ip-routing.xml
View File

@ -163,7 +163,7 @@ Destination Gateway Genmask Flags Metric Ref Use Iface
<para>
A quick glance down this routing table also provides us with a good
deal of knowledge about the topology of the network. Immediately we
can identify four separate ethernet interfaces, 3 locally connected
can identify four separate Ethernet interfaces, 3 locally connected
class C sized networks, and one tiny subnet (192.168.100.0/30). We
can also determine that there are two networks reachable via static
routes behind internal routers.
@ -246,7 +246,7 @@ Destination Gateway Genmask Flags Metric Ref Use Iface
for locally connected networks in a routing cache. After a bit of
reflection, you come to realize that there is on need to cache an IP
route for a locally connected network because the machine is
connected to the same ethernet. So, any given destination has an
connected to the same Ethernet. So, any given destination has an
entry in either the arp table or in the routing cache. For a
clearer picture of the differences between each of the cached
routse, I'd suggest adding a <option>-e</option> switch.
@ -359,7 +359,7 @@ Source Destination Gateway Flags MSS Window irtt Iface
</para>
<para>
Occasionally, however, you'll have a single machine with an IP
address in a different range on the same ethernet as some other
address in a different range on the same Ethernet as some other
machines. Or you might have a single machine which is reachable
via a router. Let's look at these two scenarios to see how we can
create static routes to solve this routing need.
@ -411,7 +411,7 @@ Destination Gateway Genmask Flags Metric Ref Use Iface
reach.
</para>
<para>
Even rarer, you may encounter a situation where a single ethernet
Even rarer, you may encounter a situation where a single Ethernet
network is used to host multiple IP networks. There are reasons
people might do this, although I regard this is bad form. If
possible, it is cleaner, more secure, and easier to troubleshoot if
@ -789,7 +789,7 @@ local 127.0.0.0/8 dev lo proto kernel scope host src 127.0.0.1</computeroutpu
<footnote>
<para>
I'm going to specifically neglect a discussion of bridging and
broadcast addresses for now. Let's assume a simple ethernet
broadcast addresses for now. Let's assume a simple Ethernet
where the entire IP network is on one hub or switch.
</para>
</footnote>.
@ -807,7 +807,7 @@ local 127.0.0.0/8 dev lo proto kernel scope host src 127.0.0.1</computeroutpu
When a user initiates a connection to localhost (let's say
localhost:25, where a private SMTP server is listening), the
connection could, of course, come from the IP assigned to any of
the ethernet interfaces. It makes the most sense, however, for the
the Ethernet interfaces. It makes the most sense, however, for the
source IP to be set to 127.0.0.1, since the connection is
actually initiated from on the local machine. Some services
running on a local machine rely on the loopback interface and