Here's result from nslookup and also resolv.conf file.

It seems the first nameserver in the list doesn't work but the second does.

Does that mean my perl program always uses the first nameserver from the list?

Any suggestions what I should do before getting to support guys?

$ /usr/sbin/nslookup www.xxxxxxxx.com
;; Got recursion not available from 172.25.226.13, trying next server
Server:         172.25.229.141
Address:        172.25.229.141#53

Non-authoritative answer:
Name:   www.xxxxxxxx.com
Address: 207.xxx.xx.xxx

$ more /etc/resolv.conf
options timeout:2 retrans:1 retry:1
domain xxxxxxxx
nameserver 172.25.226.13
nameserver 172.25.229.141
nameserver 172.25.226.16