0001 .. SPDX-License-Identifier: GPL-2.0
0002
0003 ===========
0004 IP-Aliasing
0005 ===========
0006
0007 IP-aliases are an obsolete way to manage multiple IP-addresses/masks
0008 per interface. Newer tools such as iproute2 support multiple
0009 address/prefixes per interface, but aliases are still supported
0010 for backwards compatibility.
0011
0012 An alias is formed by adding a colon and a string when running ifconfig.
0013 This string is usually numeric, but this is not a must.
0014
0015
0016 Alias creation
0017 ==============
0018
0019 Alias creation is done by 'magic' interface naming: eg. to create a
0020 200.1.1.1 alias for eth0 ...
0021 ::
0022
0023 # ifconfig eth0:0 200.1.1.1 etc,etc....
0024 ~~ -> request alias #0 creation (if not yet exists) for eth0
0025
0026 The corresponding route is also set up by this command. Please note:
0027 The route always points to the base interface.
0028
0029
0030 Alias deletion
0031 ==============
0032
0033 The alias is removed by shutting the alias down::
0034
0035 # ifconfig eth0:0 down
0036 ~~~~~~~~~~ -> will delete alias
0037
0038
0039 Alias (re-)configuring
0040 ======================
0041
0042 Aliases are not real devices, but programs should be able to configure
0043 and refer to them as usual (ifconfig, route, etc).
0044
0045
0046 Relationship with main device
0047 =============================
0048
0049 If the base device is shut down the added aliases will be deleted too.
