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.