Playing Games through linux box (HELP NEEDED)

[Da-LuK]

hello! this is my first post on a linux forum... and as you guessed, I have a problem...

I have 2 PC-s:
#1- Duron 800, 256DDR - Fedora Core 3 (used as web server, squid, DNS, ... night-time downloads, and other)
#2- AthlonXP 2500+, 512DDR - XP sp2 (used for browsing, music, movies, games, office...you get it)
My LAN diagram is:

|======|
| WWW |
|======|
|
(PPoE) - Peer2Peer over ethernet (10.0.0.0/32)
|
|======|
| DURON | ---(eth0)----ExternalLAN (192.168.0.0/21)
|======|
|
(eth1) - 192.168.25.0/24
|
|======|
| athlonXP|
|======|


1. the PPoE connection exists over ETH0.
2. the ExternalLAN is the network through witch I connect to the internet (via PPoE), and I have some friends on the LAN.
3. there is an iRC channel and a DC++ hub on the External network (both with the IP 192.168.5.1), witch I also access...
4. the DC++ hub I can only connect to in passive mode.

This brings me to my problem...

I want to play some games with my friends on the ExternalLAN, and I can't seem to make the port forwarding thing work.

the only rules in my iptables firewall are:

===========================================
int_lan=192.168.25.0/24
ext_lan=192.168.0.0/21
int_ip=192.168.25.1
ext_ip=192.168.4.79
inet_ip=10.0.0.56

iptables -t nat -F
iptables -t nat -X
iptables -F
iptables -X

echo " Enabling NAT..."
echo "1" > /proc/sys/net/ipv4/ip_forward
iptables -t nat -A POSTROUTING -s $int_lan -d ! $ext_lan -j SNAT --to $inet_ip
iptables -t nat -A POSTROUTING -s $int_lan -d $ext_lan -j SNAT --to $ext_ip

echo " Enabling Transparent SQUID Proxy-Cache"
iptables -t nat -A PREROUTING -i eth1 -p tcp --dport 80 -j REDIRECT --to-port 8080

==============================================

That's it... like I said... the only thing I want is to be able to play lan games with some friends on the External network, and for that I need some iptables rules... thanx

PS-#1: I'm not among the most experienced people when it comes to linux
PS-#2: I've been thinking... if you can spot any glitches in my already existent rules, please let me know (for example how could I connect to the DC++ hub in active mode).

[Da-LuK]

I talked to sombody, and he said it's a "simple" port forwarding problem...
The only problem is I tryed 50 port forwarding 50 times, and it never worked... I assume it's not an iptables problem... it's more of an admin problem... (yeah... that's me ). I'd like somebody to give me an example for a game, say Unreal, Warcraft, NFS... (any other will do)

[Da-LuK]

I've tried various methods, and i just can't get it to work...
does anybody know... does it matter the order of the lines in an firewall script (ex: rc.local), and by that i mean -A FORWARD should be before/after -t nat -A PREROUTING, could I do FORWARD-PREROUTE-...-FORWARD-PREROUTE or it's necessary that I group all FORWARD commands with each-other(for example FORWARD-FORWARD...PREROUTE-PREROUTE...)
I'm completly confused....