Thanks Jorg, I get the following for lsmod : [root@squidserver ~]# lsmod | grep conntrack ip_conntrack 41497 3 ipt_state,ipt_MASQUERADE,iptable_nat So how do I add : ip_conntrack_ftp ipt_conntrack And yes it is : -A FORWARD -j DROP Thanks again Varun ----- Original Message ----- From: Jörg Harmuth <harmuth@xxxxxxxxx> Date: Monday, August 15, 2005 4:29 pm Subject: Re: ftp issue cont. > varun_saa@xxxxxxxx schrieb: > > Thanks Jorg, > > How to find out if ftp-module is loaded or > > not. > > e.g. > > lsmod | grep conntrack > > gives on my box: > > ip_conntrack_ftp 3680 0 (unused) > ipt_conntrack 1120 0 (autoclean) > ip_conntrack 26484 1 (autoclean) [ip_conntrack_ftp ... > > > > > Thanks > > > > Varun > > > > ----- Original Message ----- > > From: Jörg Harmuth <harmuth@xxxxxxxxx> > > Date: Monday, August 15, 2005 2:43 pm > > Subject: Re: ftp issue cont. > > > > > >>Derick Anderson schrieb: > >> > >>>FTP passive mode creates an entirely new connection for data > >> > >>transfer.> It is not 'related' to the original connection and so > > >>iptables doesn't > >> > >>>pick it up as such (nor do any other stateful firewalls that I'm > > >> > >>aware> of). > >> > >>No, not really. Iptables regards FTP data traffic as related > stuff. To > >>be more exactly, the respective helper module does so > >>(ip_conntrack_ftp.[k]o). So, normally all you have to do, is load > this > >>module, allow ESTABLISHED,RELATED traffic in and out and allow > FTP in. > >>This looks something like this (assumed that policies are DROP > and > >>OUTPUT is ACCEPT and also assumed that the box is directly > >>connected to > >>the internet and that the FTP server is on the firewall box): > >> > >>modprobe ip_conntrack_ftp.[k]o > >> > >>iptables -A INPUT -m state --state RELATED,ESTABLISHED -j ACCEPT > >>iptables -A INPUT -p tcp --dport 21 --syn -j ACCEPT > >> > >>This will work for active and passive FTP. If the ftp-module > isn't on > >>the system in question, varun_saa has to configure the kernel > >>correctlyand recompile as needed. > >> > >>BTW, the original ruleset didn't explain anything. IN|OUTPUT == > ACCEPT > >>and in FORWARD no rule concerning FTP. So, what is this guy doing > ? If > >>the FTP server is on the firewall box, there is no iptables > problem at > >>all (on this box). If not, there are no rules that permit FTP and > thus > >>it cannot work. The whole thing looks quite mysterious to me, > >>includingthe -P issue Rob mentioned. May be a tiny ASCII art > >>network picture > >>would clarify the situation :) > >> > >>Have a nice time, > >> > >>Joerg > >> > >> > >> > >> > > > > > > > > !DSPAM:430073677568926616419! > >