162306a36Sopenharmony_ci.. SPDX-License-Identifier: GPL-2.0 262306a36Sopenharmony_ci 362306a36Sopenharmony_ci=========== 462306a36Sopenharmony_ciIP-Aliasing 562306a36Sopenharmony_ci=========== 662306a36Sopenharmony_ci 762306a36Sopenharmony_ciIP-aliases are an obsolete way to manage multiple IP-addresses/masks 862306a36Sopenharmony_ciper interface. Newer tools such as iproute2 support multiple 962306a36Sopenharmony_ciaddress/prefixes per interface, but aliases are still supported 1062306a36Sopenharmony_cifor backwards compatibility. 1162306a36Sopenharmony_ci 1262306a36Sopenharmony_ciAn alias is formed by adding a colon and a string when running ifconfig. 1362306a36Sopenharmony_ciThis string is usually numeric, but this is not a must. 1462306a36Sopenharmony_ci 1562306a36Sopenharmony_ci 1662306a36Sopenharmony_ciAlias creation 1762306a36Sopenharmony_ci============== 1862306a36Sopenharmony_ci 1962306a36Sopenharmony_ciAlias creation is done by 'magic' interface naming: eg. to create a 2062306a36Sopenharmony_ci200.1.1.1 alias for eth0 ... 2162306a36Sopenharmony_ci:: 2262306a36Sopenharmony_ci 2362306a36Sopenharmony_ci # ifconfig eth0:0 200.1.1.1 etc,etc.... 2462306a36Sopenharmony_ci ~~ -> request alias #0 creation (if not yet exists) for eth0 2562306a36Sopenharmony_ci 2662306a36Sopenharmony_ciThe corresponding route is also set up by this command. Please note: 2762306a36Sopenharmony_ciThe route always points to the base interface. 2862306a36Sopenharmony_ci 2962306a36Sopenharmony_ci 3062306a36Sopenharmony_ciAlias deletion 3162306a36Sopenharmony_ci============== 3262306a36Sopenharmony_ci 3362306a36Sopenharmony_ciThe alias is removed by shutting the alias down:: 3462306a36Sopenharmony_ci 3562306a36Sopenharmony_ci # ifconfig eth0:0 down 3662306a36Sopenharmony_ci ~~~~~~~~~~ -> will delete alias 3762306a36Sopenharmony_ci 3862306a36Sopenharmony_ci 3962306a36Sopenharmony_ciAlias (re-)configuring 4062306a36Sopenharmony_ci====================== 4162306a36Sopenharmony_ci 4262306a36Sopenharmony_ciAliases are not real devices, but programs should be able to configure 4362306a36Sopenharmony_ciand refer to them as usual (ifconfig, route, etc). 4462306a36Sopenharmony_ci 4562306a36Sopenharmony_ci 4662306a36Sopenharmony_ciRelationship with main device 4762306a36Sopenharmony_ci============================= 4862306a36Sopenharmony_ci 4962306a36Sopenharmony_ciIf the base device is shut down the added aliases will be deleted too. 50