Problem with some domains and some domain resolved

[Nayeem]

Dear All,
 

Typical problem I'm facing now that yahoo resolved and cnn give error and
google servers could not reached and we are isp and our customer suffering
now, so please help me to solve this issue.

 

Is it really  DNS problem or network problem.

 

 [root at ns1 named]# nslookup

> www.yahoo.com

Server:         127.0.0.1

Address:        127.0.0.1#53

 

Non-authoritative answer:

www.yahoo.com   canonical name = www.yahoo-ht3.akadns.net.

Name:   www.yahoo-ht3.akadns.net

Address: 87.248.113.14

> www.cnn.com

Server:         127.0.0.1

Address:        127.0.0.1#53

 

** server can't find www.cnn.com: SERVFAIL

> www.google.com

;; connection timed out; no servers could be reached

> 

 

So please tell  me where to trace this problem.

 

Really appreciated for help.

 

Regards,

Nayeem.