I have unblocked port 53 on my firewall config , but still my firewall is blocking my dns lookup.
I know the dns lookup is working because if i change my default INPUT policy to ACCEPT, then the name resolution is done correctly .
This is the iptables script
Generated by iptables-save v1.3.5 on Fri Dec 3 12:23:49 2010
*filter
:INPUT DROP [41:3304]
:FORWARD ACCEPT [0:0]
:OUTPUT ACCEPT [558:59294]
:RH-Firewall-1-INPUT - [0:0]
-A INPUT -i eth0 -p tcp -m tcp --sport 1024:65535 --dport 22 -j ACCEPT
-A INPUT -s 172.16.0.134 -p tcp -m tcp --sport 1024:65535 --dport 80 -j ACCEPT
-A INPUT -s 172.16.0.134 -p tcp -m tcp --sport 1024:65535 --dport 443 -j ACCEPT
-A INPUT -s 172.16.0.134 -p tcp -m tcp --sport 1024:65535 --dport 20 -j ACCEPT
-A INPUT -s 172.16.0.134 -p tcp -m tcp --sport 1024:65535 --dport 21 -j ACCEPT
-A INPUT -p icmp -m icmp --icmp-type any -j ACCEPT
-A INPUT -d 224.0.0.251 -p udp -m udp --dport 5353 -j ACCEPT
-A INPUT -p tcp -m tcp --dport 53 -j ACCEPT
-A INPUT -p udp -m udp --dport 53 -j ACCEPT
-A OUTPUT -s 172.16.0.4 -j DROP
-A OUTPUT -s 172.16.0.136 -j DROP
-A OUTPUT -s 172.16.0.135 -j DROP
COMMIT
# Completed on Fri Dec 3 12:23:49 2010 <code>
iptables -L yields
[root@saas-dev-dcpc ~]# iptables -L
Chain INPUT (policy DROP)
target prot opt source destination
ACCEPT tcp -- anywhere anywhere tcp spts:1024:65535 dpt:ssh
ACCEPT tcp -- 172.16.0.134 anywhere tcp spts:1024:65535 dpt:http
ACCEPT tcp -- 172.16.0.134 anywhere tcp spts:1024:65535 dpt:https
ACCEPT tcp -- 172.16.0.134 anywhere tcp spts:1024:65535 dpt:ftp-data
ACCEPT tcp -- 172.16.0.134 anywhere tcp spts:1024:65535 dpt:ftp
ACCEPT icmp -- anywhere anywhere icmp any
ACCEPT udp -- anywhere 224.0.0.251 udp dpt:mdns
ACCEPT tcp -- anywhere anywhere tcp dpt:domain
ACCEPT udp -- anywhere anywhere udp dpt:domain
Chain FORWARD (policy ACCEPT)
target prot opt source destination
Chain OUTPUT (policy ACCEPT)
target prot opt source destination
DROP all -- 172.16.0.4 anywher
DROP all -- 172.16.0.136 anywhere
DROP all -- 172.16.0.135 anywhere
Chain RH-Firewall-1-INPUT (0 references)
target prot opt source destination