Package: debian-reference-en Version: CVS HEAD Severity: wishlist Tags: patch
Section on nic interface naming is wrong for etch/udev. See attached patch. -- System Information: Debian Release: 4.0 APT prefers stable APT policy: (500, 'stable') Architecture: i386 (i686) Shell: /bin/sh linked to /bin/bash Kernel: Linux 2.6.18-5-686 Locale: LANG=en_US.UTF-8, LC_CTYPE=en_US.UTF-8 (charmap=UTF-8)
--- gateway.sgml 2007-01-12 13:33:40.000000000 -0600 +++ gateway2.sgml 2007-08-29 14:22:12.000000000 -0500 @@ -1144,74 +1144,19 @@ and should render ifupdown and friends obsolete. -<sect id="high-rename">Dealing with inconsistent naming of interfaces by the kernel +<sect id="high-rename">Dealing with the naming of interfaces <p> -The names <tt>eth0</tt>, <tt>eth1</tt>, etc. -are assigned by the kernel -in the order that the kernel creates the interfaces -that go by those names. -While adapters that are detected at boot time -are usually detected in the same order every time, -and are therefore assigned the same names every time, -the same is not true of adapters that are hot plugged. -These can be detected in any order and end up getting -assigned different names by the kernel -on different occasions. -<p> -Because of this fact, on a system into which network adapters -are hot plugged it won't always do to define logical interfaces -in <file>/etc/network/interfaces</file> with names -<tt>eth0</tt>, <tt>eth1</tt>, etc., and to rely on the -default mapping. -Instead you must give distinct names to the logical interfaces -and use one of the following two methods -to restrict which logical interfaces can be assigned -to which adapters. -<p> -This issue should be solved by using the current <package>udev</package> -package and its configuration. -<!-- -One method is to use either -the <prgn>nameif</prgn> utility -(in the <package>net-tools</package> package) -or the more flexible <prgn>ifrename</prgn> utility -(in the <package>ifrename</package> package) -to make the kernel assign names to interfaces -according to properties of the underlying adapters. -With this naming scheme in effect, -the physical interface name can be used to infer -which adapter underlies it. -<p> -Another method is to use <prgn>ifup</prgn>'s mapping mechanism -in such a way that a logical interface is chosen -for a physical interface being brought up -according to some property of the adapter -that underlies it. -<p> -Suppose, for example, you have two different network adapters -which you use with networks <tt>net1</tt> and <tt>net2</tt>, -respectively. -The <file>/usr/share/doc/ifupdown/examples/</file> directory contains -a mapping script that can be used to select a logical interface based -on the Media Access Controller address (MAC address) of the adapter. -First install the script to an appropriate directory. -<example> -# install -m770 /usr/share/doc/ifupdown/examples/get-mac-address.sh \ - /usr/local/sbin/ -</example> -Then add a stanza like the following to -<file>/etc/network/interfaces</file>: -<example> -mapping eth0 - script /usr/local/sbin/get-mac-address.sh - map 02:23:45:3C:45:3C net1 - map 00:A3:03:63:26:93 net2 -</example> -See <ref id="high-multistage-mapping"> for a more complex example. -<p> -In applying either method the property that is most commonly used -to identify the adapter is the MAC address. ---> +Udev remembers the mapping between network interface names and +network interface MAC addresses. It stores this information in +the /etc/udev/rules.d/z25_persistent-net.rules file. When, for example, +replacing a network interface card the z25_persistent-net.rules file +will need to be modified so that the name assigned to the discarded +network card will be reused. +<p> +The kernel's inconsistent naming of interfaces should be solved by +using the current <package>udev</package> +package and its configuration. If udev is not used then interface +names may not be assigned in a consistent manner, especially when hotplugged. <sect id="net-trigger">Triggering network configuration <p>
