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1.. SPDX-License-Identifier: GPL-2.02 3===========4IP-Aliasing5===========6 7IP-aliases are an obsolete way to manage multiple IP-addresses/masks8per interface. Newer tools such as iproute2 support multiple9address/prefixes per interface, but aliases are still supported10for backwards compatibility.11 12An alias is formed by adding a colon and a string when running ifconfig.13This string is usually numeric, but this is not a must.14 15 16Alias creation17==============18 19Alias creation is done by 'magic' interface naming: eg. to create a20200.1.1.1 alias for eth0 ...21::22 23 # ifconfig eth0:0 200.1.1.1 etc,etc....24 ~~ -> request alias #0 creation (if not yet exists) for eth025 26The corresponding route is also set up by this command. Please note:27The route always points to the base interface.28 29 30Alias deletion31==============32 33The alias is removed by shutting the alias down::34 35 # ifconfig eth0:0 down36 ~~~~~~~~~~ -> will delete alias37 38 39Alias (re-)configuring40======================41 42Aliases are not real devices, but programs should be able to configure43and refer to them as usual (ifconfig, route, etc).44 45 46Relationship with main device47=============================48 49If the base device is shut down the added aliases will be deleted too.50