How to 'forward port' with PPTP tunnel?

From:	"Timothy Jans" <timothy dot jans at pandora dot be>
To:	<m0n0wall at lists dot m0n0 dot ch>
Subject:	How to 'forward port' with PPTP tunnel?
Date:	Fri, 26 Mar 2004 22:47:09 +0100

Behind my m0n0wall I have a Wireless AP (on the lan interface).
Because WEP is insecure I created a PPTP tunnel from my wireless laptop to 
the m0n0wall box. All working well.

But if I want to forward a port from the WAN interface to my wireless 
laptop, do I have to use the IP adress of the wireless card or the IP adress 
of the PPTP tunnel as destination IP?