Re: Broken ftp through iptables

["Peter Marshall" <peter.marshall@caris.com>]

If you want to use passive ftp you have to allow stuff destined to port 21
and you also have to allow ( for the commands) traffic to come in on some
port that you don't get to pick.  The way to to this without actually
opening a whole bunch of ports is like this

From inside network going out and on forward chain
    -p tcp --dport  21 -j ACCEPT
    -p tcp -m state --state RELATED - j ACCEPT

FROM outside network back in on the Forward chain
   -p tcp -m state --state ESTABLISHED -j ACCEPT


If you want to do Active ftp .... well .... trust me, you dont want to do
this :)


----- Original Message -----
From: "Landon Chelf" <landonc@starrobbins.com>
To: <netfilter@lists.netfilter.org>
Sent: Tuesday, August 26, 2003 12:21 PM
Subject: Broken ftp through iptables


> Hello,
>
> I've ran into a recent problem both on rh8 and rh9 using iptables.  I've
> setup my firewall to drop everything incomming and forward and am only
> allowing certain ports to be open.  I've opened ftp (port 21 tcp) and I
> can connect via FTP from one machine and authenticate, but when I issue
> my first command like "ls" for instance the connection locks up and
> won't do anything.  Is there a way to fix this?
>
> Landon
>
>