NAT/firewall and Server 2003 RRAS

I have setup machine with 2 nics and setup RRAS.
NIC1:
172.30.x.1
255.255.240.0
no def gateway

NIC2:
DHCP

There are no filter setup on either interface in RRAS. NIC1 has been set to private interface and NIC2 has been set to Public interface and Nat enabled.

I am able to pi9ng from the internal to the external but not the other way around. Am I missing something obvious?