Need to permanently assign a static IP address to a Linux box? This tutorial describes how to add any number of IP addresses to a network interface from the console. Login as root and change directory to /etc/sysconfig/network-scripts and list the configurations of your network interface. In this example, we're assuming the network interface is eth0.
# cd /etc/sysconfig/network-scripts # ls -l ifcfg-eth0* -rw-r--r-- 1 root root 38 Dec 8 2009 ifcfg-eth0Take note of the files listed. In the above example, eth0 only has one config file, but there could be many.
# cd /etc/sysconfig/network-scripts # ls -l ifcfg-eth0* -rw-r--r-- 5 root root 235 Sep 29 2009 ifcfg-eth0 -rw-r--r-- 1 root root 237 Sep 29 2009 ifcfg-eth0:1 -rw-r--r-- 1 root root 237 Sep 29 2009 ifcfg-eth0:2 -rw-r--r-- 1 root root 237 Sep 29 2009 ifcfg-eth0:3Make a copy of the ifcfg-eth0 file and name the new file ifcfg-eth0:X where X is the next increment of the file names. For example, if there was only a single ifcfg-eth0 file, the new file should be named ifcfg-eth0:1. If the last config file was ifcfg-eth0:3, name the new file ifcfg-eth0:4.
cp ifcfg-eth0 ifcfg-eth0:1Edit the new file and change/add the settings below. The DEVICE, NETMASK, IPADDR, GATEWAY settings must be set to your specific values. For example:
# DEVICE should be the network interface name and increment DEVICE=eth0:1 IPADDR=192.168.0.102 NETMASK=255.255.255.0 GATEWAY=192.168.0.1 ONBOOT=yes BOOTPROTO=noneRepeat these steps for each IP address you need to add. For each static IP address, create a new network interface config file named with the ":X" increment, and similarly set the DEVICE directive. If you're not using DHCP at all, you may need to add/edit your DNS servers. Open up /etc/resolv.conf and make sure the IP's of your DNS servers are in there. For example:
nameserver 192.168.0.1 nameserver 192.168.0.2Finally, restart the network interfaces.
/etc/init.d/network restartIf you're SSH'd into the box, don't log out yet. Log into the box with a new SSH session to verify the network interface came back up. Once verified, try pinging the new IP from a different box.
# ping 192.168.0.102 PING 192.168.0.102 (192.168.0.102) 56(84) bytes of data. 64 bytes from 192.168.0.102: icmp_seq=1 ttl=64 time=0.051 ms 64 bytes from 192.168.0.102: icmp_seq=2 ttl=64 time=0.061 ms 64 bytes from 192.168.0.102: icmp_seq=3 ttl=64 time=0.068 ms