Remapping of starcraft UDP port 6112

["Doug C" <the_wasp@game-nation.net.nz>]

hi there everyone

i play starcraft which uses udp port 6112 all is fine unless i want 2 local comps in the same game. (changing the game port is no longer supported as blizzard feels that starcraft is "nat-friendly", however warcraft3 supports this feature)

i have attempted to write iptable configs to remap the ports but none have worked =(

i need a fully working normal nat/ip masq for other games like counter strike and for normal downloading/browsing/email etc as well as:

ClientA:
outgoing traffic on udp port 6112 from clientA to be remapped to where its already going udp port 60001
incomming traffic on udp port 60001 needs to be remapped back to clientA on upd port 6112

CLientB:
outgoing traffic on udp port 6112 from clientB to be remapped to where its already going udp port 60002
incomming traffic on udp port 60002needs to be remapped back to clientB on upd port 6112

so far i have:
******************************************************************************************************************************
ADSL=$(/sbin/ifconfig hsb0 | grep "inet addr" | awk -F: '{print $2}' | awk '{print $1}'|sed -n 1p)

iptables -A PREROUTING -t nat -j DNAT -p udp -d $ADSL --dport 63001 --to-destination 192.168.0.3:6112
iptables -A POSTROUTING -t nat -j SNAT -p udp -s $ADSL --sport 6112 --to-source 192.168.0.3:63001

iptables -A PREROUTING -t nat -j DNAT -p udp -d $ADSL --dport 63002 --to-destination 192.168.0.56:6112
iptables -A POSTROUTING -t nat -j SNAT -p udp -s $ADSL --sport 6112 --to-source 192.168.0.56:63002
******************************************************************************************************************************

starcraft sends the game packets to all other clients in the game, it does not work by sending them via a server then the server sending them to the client
ips of other people in the game will ovbiously be different from game to game
i hope you can help me

cheers
Doug