Is it possible to use NetMeeting with netfilter?

[Eric Boehm]

I am trying to setup netfilter on my firewall to redirect incoming NetMeeting
traffic to a PC running Windows 98.

My setup looks like this

 Cable <--> Linux <--> 10/100 <--> Windows 98   192.168.1.5
 Modem       FW         Hub          PC1
                              <--> Windows 95   192.168.1.3
             192.168.1.1             PC2
                              <--> iMac         192.168.1.2
                                   Virtual PC   192.168.1.4

I have a dynamic DNS name for the Linux FW.

I've tried to connect from PC2 to PC1 by going out to the Internet and back in
by specifying the dynamic DNS name as the host to connect to.

That doesn't work. I can connect from PC2 to PC1 if I use the local IP address
-- which is as expected since it doesn't go through the firewall.

Here are the rules I thought would work:

iptables -t nat -A PREROUTING -p tcp --dport 389 -i eth1 -j DNAT --to 192.168.1.5
iptables -t nat -A PREROUTING -p tcp --dport 522 -i eth1 -j DNAT --to 192.168.1.5
iptables -t nat -A PREROUTING -p tcp --dport 1503 -i eth1 -j DNAT --to 192.168.1.5
iptables -t nat -A PREROUTING -p tcp --dport 1720 -i eth1 -j DNAT --to 192.168.1.5
iptables -t nat -A PREROUTING -p tcp --dport 1731 -i eth1 -j DNAT --to 192.168.1.5

Is it possible to do this? If so, what am I doing wrong?

--
Eric M. Boehm                               boehm@nortelnetworks.com