There is no gre helper in 3.3. We use masqueragde to serve our clients. Any clients that also have a NAT router cannot connect to a pptp vpn without the gre helper. Does anyone know how we can install this helper? Thank you.
the pptp helper in 3.x includes support for GRE. Just make sure your firewall rules also accept established GRE, not just tcp/udp. A simple accept for connection-state=established without a protocol specified should work.