VPN protocols and ports

Anyone have any experience using the Nortel Contivity VPN setup with the 9000SM? We have a client that had a working connection to the East coast but not the West. When his company upgraded the East coast server he lost all VPN connectivity. Does anyone know if (UDP port 500 Protocol 50 & 51) used by the Contivity will pass on or do we need to forward specific ports and protocols within the SM