[ale] iptables port forwarding

[Jim Popovitch]

I'm brain dead tonight, at least when dealing with iptables. ;-)  What
I'm trying to do is forward a port from inside a vpn to an outside host.
Specifically I want internal users to use 192.168.10.1:25 for submitting
email to a remote host (ww.xx.yy.zz).  On the gateway server
(192.168.10.1), tap0 is the openvpn interface and eth0 is the external
interface and I'm using these rules:

iptables -t nat -A PREROUTING -p tcp -i tap0 -d 192.168.10.1
		 --dport 25 -j DNAT --to ww.xx.yy.zz:80
iptables -A FORWARD -p tcp -i tap0 -o eth0 -d 192.168.10.1 --dport 25 -j ACCEPT

The problem is that telnet'ing to 192.168.10.1 port 25 doesn't work.  Any ideas?

-Jim P.