From mboxrd@z Thu Jan  1 00:00:00 1970
From: Bernd Podey <Bernd.Podey@gmx.de>
Subject: Re: Problem with iptables -A FORWARD -j DROP
Date: Thu, 20 Feb 2003 12:37:45 +0100
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To: =?ISO-8859-1?Q?Gabriel_G=FCeto?= <gabriel.gueto@rhodasol.turimar.es>
Cc: netfilter@lists.netfilter.org

Gabriel G=FCeto wrote:
> Hello, I'm installing a bridge-firewall an all is OK, but whe I deny al=
l=20
> the 'FORWARD' traffic this rule deny all the traffic included the=20
> 'ACCEPT' rules. Mi Kernel is 2.4.18
> and i installed itables 1.2.5-3. My script is:
> =20
> iptables -F FORWARD
> iptables -F INPUT
> iptables -F OUTPUT
> =20
> iptables -A FORWARD -p icmp -s 89.0.0.0/24 -d 89.0.0.55/32 -j ACCEPT
> =20
> iptables -A FORWARD -j DROP
> =20
> =20
> =20
> If I quit the las line it's all OK, if I deny 'ping' it's OK, but if I=20
> put the last line all ping are deny.
> =20
> Can somebody help me. I'm sorry for mu poor English.
> =20
> Gabriel.
Hello!

You have to allow both communication directions!

Try the following:
iptables -A FORWARD -p icmp -s 89.0.0.0/24 -d 89.0.0.55/32 -j ACCEPT
iptables -A FORWARD -p icmp -s 89.0.0.55/32 -d 89.0.0.0/24 -j ACCEPT

iptables -A FORWARD -j DROP

and everything will work fine

Bernd