Port Forwarding Script Not Working

r00t440 · Tux's lil' helper Joined: 13 Sep 2005 Posts: 77

Here's a port forwarding script I copied over the internet, can anyone spot any problem with it? It doesn't seem to work as expected. I use ipkungfu as my firewall script.
I've been working on this for almost a whole day, I'm running out of ideas. Thanks in advance to anyone who can help me.

mks99 · n00b Joined: 10 Dec 2004 Posts: 58

The second rule changes the dest. IP of the packets to $PORTFWIP and passes them to the FORWARD chain. OK.
The first rule allows those packets to be forwarded. OK.
But I don't see any sense in the third rule. Of course, there has to be done some MASQUERADEing since the reply-packets from $PORTFWIP must have their src IP changed to $EXTIP. But this should be accomplished by a rule like

r00t440 · Tux's lil' helper Joined: 13 Sep 2005 Posts: 77

thanks... i tried your suggestions but still i'm totally lost. i've read a guide from gentoo-wiki.com (http://gentoo-wiki.com/HOWTO_setup_a_home-server) and adapted the eMule port-forwarding part, but still no luck. By the way, i'm using ipkungfu as my firewall script. There's a part in ipkungfu's config files which is all about port forwarding and i've tried modifying it. But still port 6200 on my external ip is closed when performing a portscan against it.

I'm very tired now so I guess I'll work on this by tomorrow. I'm gonna try the following:

1. I won't use ipkungfu and try my port forwarding scripts.
2. I'm gonna try my new kernel (I might have missed something from my current kernel)
3. Read my post and hope that somebody has come across with it and was kind enough to offer some suggestions/help.

oh by the way, here's the output of "iptables -nvL", this might be of some help: