1. Edit resolv.conf and use your chosen name servers. Here we are using Google DNS.
> vi /etc/resolv.conf
nameserver 8.8.8.8 nameserver 8.8.4.4
2. To prevent your resolv.conf from being overwritten on reboot, also change ifcfg-eth0.
> vi /etc/sysconfig/network-scripts/ifcfg-eth0
DNS2=8.8.4.4 DNS1=8.8.8.8