1*735dadf8STobin C. Harding.. SPDX-License-Identifier: GPL-2.0 2*735dadf8STobin C. Harding 3*735dadf8STobin C. Harding=========== 4*735dadf8STobin C. HardingIP-Aliasing 5*735dadf8STobin C. Harding=========== 6*735dadf8STobin C. Harding 7*735dadf8STobin C. HardingIP-aliases are an obsolete way to manage multiple IP-addresses/masks 8*735dadf8STobin C. Hardingper interface. Newer tools such as iproute2 support multiple 9*735dadf8STobin C. Hardingaddress/prefixes per interface, but aliases are still supported 10*735dadf8STobin C. Hardingfor backwards compatibility. 11*735dadf8STobin C. Harding 12*735dadf8STobin C. HardingAn alias is formed by adding a colon and a string when running ifconfig. 13*735dadf8STobin C. HardingThis string is usually numeric, but this is not a must. 14*735dadf8STobin C. Harding 15*735dadf8STobin C. Harding 16*735dadf8STobin C. HardingAlias creation 17*735dadf8STobin C. Harding============== 18*735dadf8STobin C. Harding 19*735dadf8STobin C. HardingAlias creation is done by 'magic' interface naming: eg. to create a 20*735dadf8STobin C. Harding200.1.1.1 alias for eth0 ... 21*735dadf8STobin C. Harding:: 22*735dadf8STobin C. Harding 23*735dadf8STobin C. Harding # ifconfig eth0:0 200.1.1.1 etc,etc.... 24*735dadf8STobin C. Harding ~~ -> request alias #0 creation (if not yet exists) for eth0 25*735dadf8STobin C. Harding 26*735dadf8STobin C. HardingThe corresponding route is also set up by this command. Please note: 27*735dadf8STobin C. HardingThe route always points to the base interface. 28*735dadf8STobin C. Harding 29*735dadf8STobin C. Harding 30*735dadf8STobin C. HardingAlias deletion 31*735dadf8STobin C. Harding============== 32*735dadf8STobin C. Harding 33*735dadf8STobin C. HardingThe alias is removed by shutting the alias down:: 34*735dadf8STobin C. Harding 35*735dadf8STobin C. Harding # ifconfig eth0:0 down 36*735dadf8STobin C. Harding ~~~~~~~~~~ -> will delete alias 37*735dadf8STobin C. Harding 38*735dadf8STobin C. Harding 39*735dadf8STobin C. HardingAlias (re-)configuring 40*735dadf8STobin C. Harding====================== 41*735dadf8STobin C. Harding 42*735dadf8STobin C. HardingAliases are not real devices, but programs should be able to configure 43*735dadf8STobin C. Hardingand refer to them as usual (ifconfig, route, etc). 44*735dadf8STobin C. Harding 45*735dadf8STobin C. Harding 46*735dadf8STobin C. HardingRelationship with main device 47*735dadf8STobin C. Harding============================= 48*735dadf8STobin C. Harding 49*735dadf8STobin C. HardingIf the base device is shut down the added aliases will be deleted too. 50