iptables forwarding help pls

Shwick · Sep 25, 2008, 06:39 AM

I successfully set up my home network with ip forwarding and masquerading, internet <<>> ubuntu gateway <<>> local machines.

Now i'm trying to forward a port from my ubuntu gateway to one of the machines on my lan.

Specifically I need to forward port 6112 so that I can host warcraft games. These two rules don't seem to be working.

#set DNAT
iptables -A PREROUTING -t nat -p tcp --dport 6112 -i eth0 -j DNAT --to 192.168.0.100:6112
iptables -A PREROUTING -t nat -p udp --dport 6112 -i eth0 -j DNAT --to 192.168.0.100:6112

These were some other rules I already had.

#setup MASQUERADING for nat
iptables -A POSTROUTING -t nat -j MASQUERADE

# Setup port forwarding
iptables -A FORWARD -i eth0 -o eth1 -s 192.168.0.0/24 -m state --state NEW -j ACCEPT
iptables -A FORWARD -m state --state ESTABLISHED,RELATED -j ACCEPT

I set up a log after the DNAT and it gets triggered b/c I can see it in syslog, but no one can join my games.
I also set up a log after MASQUERADE but that one didn't appear in syslog.

Maybe it has something to do with state in the DNAT rules? I dunno whats going on.

Shwick · Sep 26, 2008, 02:24 AM

Stupid Windows SP3 didn't ask me if I wanted to allow War3 through my firewall. I added it manually and now my windows machine can host through the gateway. The packets were being forwarded properly all along I was just so focused on the gateway being the problem. Next time I'll install wireshark.

Sep 25, 2008, 06:39 AM	#1
Shwick DriverHeaven Newbie Join Date: Mar 2007 Posts: 16 Rep Power: 0	iptables forwarding help pls I successfully set up my home network with ip forwarding and masquerading, internet <<>> ubuntu gateway <<>> local machines. Now i'm trying to forward a port from my ubuntu gateway to one of the machines on my lan. Specifically I need to forward port 6112 so that I can host warcraft games. These two rules don't seem to be working. #set DNAT iptables -A PREROUTING -t nat -p tcp --dport 6112 -i eth0 -j DNAT --to 192.168.0.100:6112 iptables -A PREROUTING -t nat -p udp --dport 6112 -i eth0 -j DNAT --to 192.168.0.100:6112 These were some other rules I already had. #setup MASQUERADING for nat iptables -A POSTROUTING -t nat -j MASQUERADE # Setup port forwarding iptables -A FORWARD -i eth0 -o eth1 -s 192.168.0.0/24 -m state --state NEW -j ACCEPT iptables -A FORWARD -m state --state ESTABLISHED,RELATED -j ACCEPT I set up a log after the DNAT and it gets triggered b/c I can see it in syslog, but no one can join my games. I also set up a log after MASQUERADE but that one didn't appear in syslog. Maybe it has something to do with state in the DNAT rules? I dunno whats going on.

Sep 26, 2008, 02:24 AM	Thread Starter #2
Shwick DriverHeaven Newbie Join Date: Mar 2007 Posts: 16 Rep Power: 0	Stupid Windows SP3 didn't ask me if I wanted to allow War3 through my firewall. I added it manually and now my windows machine can host through the gateway. The packets were being forwarded properly all along I was just so focused on the gateway being the problem. Next time I'll install wireshark.