1*4882a593Smuzhiyun.. SPDX-License-Identifier: GPL-2.0 2*4882a593Smuzhiyun 3*4882a593Smuzhiyun=========== 4*4882a593SmuzhiyunIP-Aliasing 5*4882a593Smuzhiyun=========== 6*4882a593Smuzhiyun 7*4882a593SmuzhiyunIP-aliases are an obsolete way to manage multiple IP-addresses/masks 8*4882a593Smuzhiyunper interface. Newer tools such as iproute2 support multiple 9*4882a593Smuzhiyunaddress/prefixes per interface, but aliases are still supported 10*4882a593Smuzhiyunfor backwards compatibility. 11*4882a593Smuzhiyun 12*4882a593SmuzhiyunAn alias is formed by adding a colon and a string when running ifconfig. 13*4882a593SmuzhiyunThis string is usually numeric, but this is not a must. 14*4882a593Smuzhiyun 15*4882a593Smuzhiyun 16*4882a593SmuzhiyunAlias creation 17*4882a593Smuzhiyun============== 18*4882a593Smuzhiyun 19*4882a593SmuzhiyunAlias creation is done by 'magic' interface naming: eg. to create a 20*4882a593Smuzhiyun200.1.1.1 alias for eth0 ... 21*4882a593Smuzhiyun:: 22*4882a593Smuzhiyun 23*4882a593Smuzhiyun # ifconfig eth0:0 200.1.1.1 etc,etc.... 24*4882a593Smuzhiyun ~~ -> request alias #0 creation (if not yet exists) for eth0 25*4882a593Smuzhiyun 26*4882a593SmuzhiyunThe corresponding route is also set up by this command. Please note: 27*4882a593SmuzhiyunThe route always points to the base interface. 28*4882a593Smuzhiyun 29*4882a593Smuzhiyun 30*4882a593SmuzhiyunAlias deletion 31*4882a593Smuzhiyun============== 32*4882a593Smuzhiyun 33*4882a593SmuzhiyunThe alias is removed by shutting the alias down:: 34*4882a593Smuzhiyun 35*4882a593Smuzhiyun # ifconfig eth0:0 down 36*4882a593Smuzhiyun ~~~~~~~~~~ -> will delete alias 37*4882a593Smuzhiyun 38*4882a593Smuzhiyun 39*4882a593SmuzhiyunAlias (re-)configuring 40*4882a593Smuzhiyun====================== 41*4882a593Smuzhiyun 42*4882a593SmuzhiyunAliases are not real devices, but programs should be able to configure 43*4882a593Smuzhiyunand refer to them as usual (ifconfig, route, etc). 44*4882a593Smuzhiyun 45*4882a593Smuzhiyun 46*4882a593SmuzhiyunRelationship with main device 47*4882a593Smuzhiyun============================= 48*4882a593Smuzhiyun 49*4882a593SmuzhiyunIf the base device is shut down the added aliases will be deleted too. 50