IP-Aliasing:
IP-aliases are an obsolete way to manage multiple IP-addresses/masks
per interface. Newer tools such as iproute2 support multiple
address/prefixes per interface, but aliases are still supported
for backwards compatibility.
An alias is formed by adding a colon and a string when running ifconfig.
This string is usually numeric, but this is not a must.
o Alias creation.
Alias creation is done by ‘magic’ interface naming: eg. to create a
200.1.1.1 alias for eth0 …
# ifconfig eth0:0 200.1.1.1 etc,etc....
~~ -> request alias #0 creation (if not yet exists) for eth0
The corresponding route is also set up by this command.
Please note: The route always points to the base interface.
o Alias deletion.
The alias is removed by shutting the alias down:
# ifconfig eth0:0 down
~~~~~~~~~~ -> will delete alias
o Alias (re-)configuring
Aliases are not real devices, but programs should be able to configure and
refer to them as usual (ifconfig, route, etc).
o Relationship with main device
If the base device is shut down the added aliases will be deleted
too.
