Configure IP address in Redhat 6

Configure on commad-line by edit configuration file (Permanently)

1. Open Terminal.
2. Open network configuration file. In this example, it’ll configure on interface eth0. Type
   

   vi /etc/sysconfig/network-scripts/ifcfg-eth0

   
3. The current configuration is DHCP.
   
4. Modify the file by press ‘i’ to enter insert mode. Change BOOTPROTO to static and add IP Address and Net mask as new lines if they’re not existed yet..
   

   BOOTPROTO=static
   IPADDR=192.168.125.10
   NETMASK=255.255.255.0

   Save the configuration file by press ESC + ‘:’ and type ‘wq’ to write and quit the editor.
   
5. You can added these configuration to the config file. Replace [number] with your actual value.
   

   GATEWAY=[number]
   TYPE=Ethernet
   NETWORK=[number]
   BROADCAST=[number]

6. Restart the network interface card. Type
   

   service network restart

   
7. Review the configuration. Type
   

   ifconfig

   . The IP Address has been changed permanently.
   

source - http://www.linglom.com/2008/04/20/how-to-change-ip-address-on-linux-redhat/