#!/bin/sh
nic #
 # setup port/protocol forward to east
nic #
 iptables -t nat -I PREROUTING -p udp -d 192.1.3.254 --dport 500 -j DNAT --to-destination 192.1.2.23
nic #
 iptables -t nat -I PREROUTING -p esp -d 192.1.3.254 -j DNAT --to-destination 192.1.2.23
nic #
 # Display the table, so we know it is correct.
nic #
 iptables -t nat -L
Chain PREROUTING (policy ACCEPT)
target     prot opt source               destination         
DNAT       esp  --  anywhere             nic                  to:192.1.2.23
DNAT       udp  --  anywhere             nic                  udp dpt:isakmp to:192.1.2.23
Chain INPUT (policy ACCEPT)
target     prot opt source               destination         
Chain OUTPUT (policy ACCEPT)
target     prot opt source               destination         
Chain POSTROUTING (policy ACCEPT)
target     prot opt source               destination         
nic #
 echo "initdone"
initdone