Assigning Multiple Addresses to a Network Interface
ip Streamlines Advanced Networking
# ip addr add 192.168.1.10/24 brd + dev eth0 # ip addr add 192.168.2.10/24 brd + dev eth0
$ ip addr show eth0 2: eth0:
If you run ifconfig to check your addresses, it will see only the first one.
This is a great way to get access to multiple subnets without having to create a herd of new configurations, or install multiple network interface cards. Another practical use for this is accessing a new server or router for the first time. Typically, these come with a default IP address. If it's on a different subnet, but on the same switch, you can quickly add a compatible address to your workstation and log in to the new device. When you're finished, remove the unwanted addresses like so:
# ip addr del 192.168.3.10/24 dev eth0
man ip is the best and most complete reference.
Article courtesy of Serverwatch.com, originally published June 16, 2008