I have a CentOS 6 x86 server. If I ping 8.8.8.8 and my server gateway, there's no problem. If I ping google.com, yahoo.com, etc, it returns "ping: unknown host google.com".
When I saw this problem, first thing I go to check is the /etc/resolv.conf file, but this file seems no problem. Where else should I check?
nameserver 8.8.8.8
nameserver 8.8.4.4
Few things you can try
Look at
/etc/nsswitch.conf
Look for hosts: and see if it has dns listed
Then try to query google.com from their nameservers.. maybe output dns requests are failing
nslookup google.com 8.8.8.8
If that fails.. then
telnet 8.8.8.8 53
If you get a connection refused.. your ISP might be blocking your dns requests and you have to use their resolvers.
Do you maybe have a firewall in between which is blocking DNS traffic? You can try to make a lookup with dig and see if it works or not:
dig @8.8.8.8 www.google.com
If this does not work then it is probably a device (firewall) in between which is blocking your DNS traffic.
It seems that you don't have internet access at all, don't you?
If this is the case, have a look at your routing table using command route.
If you don't see a line like this one:
default 8.8.8.4 0.0.0.0
you probably have a gateway problem, check your network settings.
