"Saurabh Mehrotra" writes: > I am using Red Hat Enterprise Linux AS release 4 (Nahant Update 3) with > Kernel 2.6.9-34.ELsmp #1 > > I am using Iptables for firewall . > > But without firewall I m able to nslookup my own DNS server but whenever I > enabled firewall I am not able to nslookup to my own system. It sounds like your firewall is blocking DNS traffic. You'll have to show us your firewall rules if we're going to be able to help you: iptables -v -L Cheers, -Ted