your linksys router probably had your windows machine as default nat destination causing all (outside)ports of the linksys router to be forwarded to the windows machine (thus putting your windows machine directly accessible, not so good).
So now you're having a linux firewall machine as router in between ?
You're wanting let's say port 6859 on the outside of your router to be forwarded to the same port of your windows machine (change it in your azureus preferences, or get it there what your machine is trying to use).
I'm not using iptable (anymore) but I guess you could be helping yourself googling for
"port forwarding" iptable
I guess this (no guarantee) will help you:
Code:
# Azureus Port
portnr=6859
# ip-address of your windows machine.
# Get it by Start->run->cmd
# and execute "ipconfig"
windows=192.168.0.101
insidedev=eth0
outsidedev=eth1
iptables -A PREROUTING -t nat -i ${outsidedev} -p tcp --dport ${portnr} -j DNAT --to ${windows}:${portnr}
iptables -A INPUT -p tcp -m state --state NEW --dport ${portnr} -i ${outsidedev} -j ACCEPT
info found on
http://www.debian-administration.org/articles/73