(non-router) Port-Forward

A: stone (relativ langsam, aber userspace prog)
B: iptables:

#!/bin/bash
YourIP=1.2.3.4
YourPort=9999
TargetIP=2.3.4.5
TargetPort=8888
IPT="/sbin/iptables"

$IPT -t nat -A PREROUTING --dst $YourIP -p tcp --dport $YourPort -j DNAT
--to-destination $TargetIP:$TargetPort
$IPT -t nat -A POSTROUTING -p tcp --dst $TargetIP --dport $TargetPort -j
SNAT --to-source $YourIP
#$IPT -t nat -A OUTPUT --dst $YourIP -p tcp --dport $YourPort -j DNAT
--to-destination $TargetIP:$TargetPort