Problem with using Server 2008 as simple router

I have the following setup

One server has two interfaces, one public and one private one.

The public interface is a 192.168.10.0 /24 network and the private one a 172.168.1.0 /24

Server 1
Nic 1 :
IP : 192.168.10.191  
Mask : /24
Gateway : 192.168.10.1
DNS : localhost (local DNS forwards requests to an external DNS server)

Nic 2 :
IP : 172.168.1.1
Mask : /24
Gateway : n/a
DNS : localhost

Server 2 :
Nic 1 :
IP : 172.168.1.2
Mask : /24
Gateway : 172.168.1.1
DNS : 172.168.1.1

I have then added the Routing role to server 1 (2008 Enterprise) and started / configured RRAS with "custom" and "lan routing only".

What settings do I have to do to "make it work" ?

I can ping the rras server from the 2nd member server and using nslookup shows that DNS resolution works as well, but there is no internet connectivity.