> You cannot NAT/forward random ports
> through a firewall when you don't know which they are.

That's right, but this random port is choosen from some range. IIRC,
it is 1024-65535. Are you sure that command
iptables -t nat -A PREROUTING -p tcp -d 15.45.23.67 --dport
1024-65535 -j DNAT --to-destination 192.168.1.1

won't work? I'm not.

SY, SD.