OK, vpn server is in usa client is in uk. the network is as follows top down; - Internet cloud - lucent cell pipe router connect to internet - firwall (Cisco PIX 501 Firewall) links up with router, which in turns linked to uplink switch port - PC connected to switch. Additional info; router allows vpn passthrough and I found out that from broadband provider that no ports are blocked. on Client XP PC the connection is created using pptp but returns error 721. I suspect its the firewall that is blocking it cause router is vpn pass-through, and I am can't access the router anyway but firewall i can. I know this is a difficult proposition and not enough info is provided but any positive feedback will be appreciated simon

Set up port forwarding on TCP1723, and forward type 47 (GRE) packets.