Based on kernel version 4.16.1. Page generated on 2018-04-09 11:53 EST.
1 2 IP-Aliasing: 3 ============ 4 5 IP-aliases are an obsolete way to manage multiple IP-addresses/masks 6 per interface. Newer tools such as iproute2 support multiple 7 address/prefixes per interface, but aliases are still supported 8 for backwards compatibility. 9 10 An alias is formed by adding a colon and a string when running ifconfig. 11 This string is usually numeric, but this is not a must. 12 13 o Alias creation. 14 Alias creation is done by 'magic' interface naming: eg. to create a 15 200.1.1.1 alias for eth0 ... 16 17 # ifconfig eth0:0 200.1.1.1 etc,etc.... 18 ~~ -> request alias #0 creation (if not yet exists) for eth0 19 20 The corresponding route is also set up by this command. 21 Please note: The route always points to the base interface. 22 23 24 o Alias deletion. 25 The alias is removed by shutting the alias down: 26 27 # ifconfig eth0:0 down 28 ~~~~~~~~~~ -> will delete alias 29 30 31 o Alias (re-)configuring 32 33 Aliases are not real devices, but programs should be able to configure and 34 refer to them as usual (ifconfig, route, etc). 35 36 37 o Relationship with main device 38 39 If the base device is shut down the added aliases will be deleted 40 too.