I have a a Centos PC with 2 IP addresses. One of them is because of a back to back connection with another PC, so both run on different subnets. The eth0 has the 192.xx.xx.xxx address and eth2 has 172.xx.xx.xxx on this PC.

Since 192.xx.xx.xxx is a back to back connection it doesn't have internet capability, but 172.xx.xx.xxx does. The default is set to 192.xx.xx.xxx, so whenever I do a yum update or anything it goes through 192.xx.xx.xxx, it is not able to perform the update or I am not even able to ping www.google.com.

Is there a way I can set the default IP address for eth2 to, e.g., 172.xx.xx.xxx?

I have already tried going to the /etc/sysconfig/network and setting the gateway to 172.x.y.z, but it didnt work .

1 Answer 1


You need to setup the default gateway....you must know the router address off the 172 network to do this.

Open /etc/sysconfig/network file:

 vi /etc/sysconfig/network

Setup GATEWAY={Router-IP}, if router IP is 172.x.y.z, type:


Save and close the file. Here would be the completed file:

  • Tried your above suggestion already, didnt work for me. Thats why came to this forum for suggestions.
    – vadugs
    Commented Jan 8, 2013 at 18:59

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