Question : Problem: What are the correct ports to forward for an XP VPN?

This is a continuation of this question: http://www.experts-exchange.com/Networking/Q_21838629.html but this is different enough that I'm opening this thread.

What I've found when searching for port information is conflicting. This is a simple XP VPN to XP VPN. What ports do I need to forward, and are there any other tricks to getting filesharing working using the actual computer names? I've heard of issues where you can't browse for the names, but can connect if you manually map the share using the "local" IP.

Answer : Problem: What are the correct ports to forward for an XP VPN?

You say above you are able to connect but you cannot ping.
-it can be due to the Windows firewall or another on the computer you are connecting to. Ping requests are denied by default. Try disabling the firewall if enabled.
-it can be due to blocked GRE traffic which is protocol 47 (not port 47). If using a router you will need to enable that. On commercial routers such as a Cisco there are specific commands. On most home and small office routers it is called "PPTP pass-through". I believe on some of the Netgears, which you mention in a previous post, it is enabled with port forwarding of port 1723. A few routers and modems to not support VPN traffic. I can confirm configuration and functionality if you wish to post router and modem makes and models.

Also to confirm it would be nice to know if your router has a true public IP as asked above. This can be an issue, but if you have a connection it is likely fine.