Error 721 while connection to WinXP Pro VPN

[Sohil]

I am trying connect to my Windows XP Professional PC at
home sitting behind a firewall. I am using NAT. I have
forwarded TCP port 1723 to the XP machine. I have verified
that the VPN host and client work by connecting over the
LAN. When I the laptop outside the LAN, I can't connect to
the XP machine. It seems to connect up to the XP machine,
and fails when "Verifying username and password"
with "Error 721: The computer is not responding". When I
run netstat -an, shows that the connection is established.

I hope someone can help me with this. I am in desperate
need for help.

Thanks
Sohil

 

[Dusty Harper {MS}]

you also need to forward protocol 47 ( GRE ). ( on some routers, this is
called VPN Pass through )

 

[Guest]

Have a check of this

http://support.microsoft.com/default.aspx?kbid=810839

 

[Guest]

Dusty,

Thanks for your reply.

I am using port forwarding for my LinkSys. I am forwarding
47 (GRE) and 1723 (PPTP) to my machine.

The odd thing is that the VPN Client says it's connected
(using netstat -an). I think there may be an issue after
the connection. Can you tell me what happens once the link
is established and username/password is sent to the host.
I think the VPN Client is waiting for the host to reply
but never gets one.