Hello all:

I searched and searched this forum, and could not find the answer. I know its probably simple, but everything I find cannot make it work.

I am using Slack 2.4.19. I have my "firewall" using IP masquerading (iptables) set up as 192.168.0.1. I have a Windows computer BEHIND that firewall at 192.168.0.2 running BulletProof FTP. What is the command to forward port 21 for using FTP services to 192.168.0.2, so that if someone ftp's to my external IP, it will forward to 192.168.0.2 INTERNALLY.

PLEASE HELP!!!!!!!!!!!!!!!!!!!!!!!!!

My favourite tutorial is here
http://www.netfilter.org/documentati...ials/blueflux/

and you need a -j DNAT in the PREROUTING chain for port 20.

Regards,
Peter

Shouldn't it be port 21??? I tried the following line to no avail:

iptables -t nat -A PREROUTING -p tcp --dport 21 -i eth0 -j DNAT --to 192.168.0.2:21

Any help will be appreciated.

FTP uses two ports: 20 for data and 21 for commands. You'll need to make sure that both ports pass through. In addition, passive versus active FTP might be the culprit.

Well, as the last suggestion stated, I now have the following lines:

iptables -t nat -A PREROUTING -p tcp --dport 21 -i eth0 -j DNAT --to 192.168.0.2:21
iptables -t nat -A PREROUTING -p tcp --dport 20 -i eth0 -j DNAT --to 192.168.0.2:20

Still no go.

Any ideas what I should change the commands to?

PLEASE HELP!!!!!!!!!!!!!

ANYONE???

Are you using passive or active FTP transfers?

What do you mean exactly??? I guess I am using whatever Windows does, because Bulletproof FTP is on Windows.

Active ftp uses port 20 and 21.

Passive ftp really sucks if you are setting up a good firewall. It uses port 20 and it takes a random port above port 1024. The best way to enable passive ftp on your firewall is with modules for connection tracking. I've tryed it myself once and i couldnt make it work. It just opened all ports above port 1024, not for only ftp but for all services.

To set your ftp program to passive or to active ftp, you could try the command: pasv