ERROR 800 conecting to NT4 VPN server using XP PRO

[Scott]

I have a VPN connectin that was working flawlessly as of
this Monday.

The only change has been Critical Updates to an XP Pro
workstation.

While attempting to connect to the VPN IP "error 800
unable to establish vpn connection" comes up

I have recycled power on the cisco 1721 router and
verfied with their techs that the config file has not
been changed.

I have recycled the VPN service on the NT4 Server

I can connect to the VPN server if I use the
internal 'private' IP just not the outside one.

I plan on rebooting the NT4 server for the first time in
over a year.

Any thoughts?

 

[Sharoon Shetty K [MSFT]]

Is there any firewall settings on the client?