configuring 2 IPs on Single Network interface in CentOS 5.8

[nileshkumar]

Hi all, I want to configure 2 IPs (of diffrent Network like 10.40.60.21/24 and 172.16.16.12/24 with default gatways as 172.16.16.10/32) on Single Network Interface Card. Also then i want to modify the default routing on my system. So can anyone help me on this

[srj]

Hello,

One sollution using the "ifconfig" command:

ifconfig eth0:1 <new_ip> netmask <new_netmask>

This will create a virtual network eth0:1 with the new desired settings.

To make this network available after every restart you will need to change some configuration files. I hope this guide will help you with this: Chapter*13.*Network Interfaces

Cheers,
Srj

[atreyu]

I prefer to use ip (from the iproute package) as it is more capable than ifconfig, and is slowly replacing ifconfig everywhere. here is an example of usage:

ip addr add 192.168.1.2/24 dev eth0
ip addr add 10.1.1.2/24 dev eth0

if you really want, you can assign aliases to them (like eth0:0) if you want, but I find those confusing (and iptables doesn't like them!).

[nileshkumar]

Thanku guys for your response, but i have a few questions, that i want to change the IP add of my interface regularly, as my connection to internet is through proxy, and to access net i have to change my IP.
And next thing is with 2 IPs configured, and one default gateway, i have to add routes so that packets for local network send on another gateway and all other packets are send on default gateway, so how to configure that.