network Problem with unix open solaris

Dear Member:-
Kindly be I am facing a problem with my open Solaris release b101
1- vi /etc/hostname.reg0
This is my IP address xx.xx.xx.xx
2- vi /etc/netmasks
This is my subnet mask
3- vi /etc/defaultrouter
This is my gateway
4- vi /etc/resolv.conf
This is my DNS written with this way
Example:-
nameserver xx.xx.xx.xx
nameserver xx.xx.xx.xx

The problem is:-
1- I can't brows any web site

2- When I write this command
# ping 4.2.2.2
4.2.2.2 is alive
# ping Yahoo!
Yahoo! unknown host

What is the problem and how to solve it?

The problem is that you can't ping a logo.

Try pinging the website instead: Yahoo!

edit: Perhaps not. Seems to be a vBulletin quirk (URL renaming, that is).

Anyway, try

dig www.yahoo.com

So, your DNS lookups are cooked. Try restarting nscd via svcadm (don't refresh; must stop and start). Also, check to see that you have the correct "etc/nsswitch.conf" file. You will need "hosts files dns" entry in yours. Look at /etc/nsswitch.dns for the correct line. Also, another thing to check is whether you can resolve the name of a server if its entry is in the hosts file.