FC3 problem with ip_forward / masquerade : no more DNS resolution

[Pierre-Yves Berger]

Hello,

I just installed FC3 on a system I use as nat.
eth0 gets a dynamic address from my ISP.
eth1 has a static local address.

I did the configuration as described in the NAT-HOWTO document
at www.netfilter.org.

Now, from the computers on my local network, I cannot access Internet
using the names. I can access everything with ip numeric addresses.
 From the nat computer, I can access everything (names and numeric 
addresses).
The computers on the local network have correct DNS entries and worked
correctly before I swapped my old (hardware) unstable FC2 box with a 
newer FC3 box.

What changed between FC2 and FC3 that could cause that problem and 
where should I look
for answers ? I didn't see anything in /var/log/messages or 
/var/log/secure but I don't
really know what to look for.

Any ideas ?

Thanks,
Pierre-Yves

Output from iptables-save:
# Generated by iptables-save v1.2.11 on Thu Nov 11 18:09:21 2004
*filter
:INPUT ACCEPT [0:0]
:FORWARD ACCEPT [0:0]
:OUTPUT ACCEPT [26151:2638101]
:RH-Firewall-1-INPUT - [0:0]
-A INPUT -j RH-Firewall-1-INPUT
-A FORWARD -j RH-Firewall-1-INPUT
-A RH-Firewall-1-INPUT -i lo -j ACCEPT
-A RH-Firewall-1-INPUT -p icmp -m icmp --icmp-type any -j ACCEPT
-A RH-Firewall-1-INPUT -p ipv6-crypt -j ACCEPT
-A RH-Firewall-1-INPUT -p ipv6-auth -j ACCEPT
-A RH-Firewall-1-INPUT -d 224.0.0.251 -p udp -m udp --dport 5353 -j 
ACCEPT
-A RH-Firewall-1-INPUT -p udp -m udp --dport 631 -j ACCEPT
-A RH-Firewall-1-INPUT -m state --state RELATED,ESTABLISHED -j ACCEPT
-A RH-Firewall-1-INPUT -p tcp -m state --state NEW -m tcp --dport 22 -j 
ACCEPT
-A RH-Firewall-1-INPUT -p tcp -m state --state NEW -m tcp --dport 80 -j 
ACCEPT
-A RH-Firewall-1-INPUT -j REJECT --reject-with icmp-host-prohibited
COMMIT
# Completed on Thu Nov 11 18:09:21 2004
# Generated by iptables-save v1.2.11 on Thu Nov 11 18:09:21 2004
*nat
:PREROUTING ACCEPT [25231:1564806]
:POSTROUTING ACCEPT [21:1288]
:OUTPUT ACCEPT [33:3592]
-A POSTROUTING -o eth0 -j MASQUERADE
COMMIT
# Completed on Thu Nov 11 18:09:21 2004