1
2IP-Aliasing:
3============
4
5IP-aliases are an obsolete way to manage multiple IP-addresses/masks
6per interface. Newer tools such as iproute2 support multiple
7address/prefixes per interface, but aliases are still supported
8for backwards compatibility.
9
10An alias is formed by adding a colon and a string when running ifconfig.
11This string is usually numeric, but this is not a must.
12
13o 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
24o Alias deletion.
25  The alias is removed by shutting the alias down:
26
27    # ifconfig eth0:0 down
28                 ~~~~~~~~~~ -> will delete alias
29
30  		   		   
31o 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
37o Relationship with main device
38
39  If the base device is shut down the added aliases will be deleted 
40  too.
41