Here are the troubleshooting steps for a RAS Error 800:
Error 800: Unable to establish the VPN connection. The VPN server may
be un-reachable, or security parameters may not be configured properly
for this connection.
Resolutions:
1) if you have firewall, open TCP Port 1723, IP Protocol 47 (GRE).
2) make sure you can reach the VPN server by using ping. Sometimes,
poor connection can cause this issue too.
3) You may need to updated firmware on a router or firewall if other
OS (win9x/nt/me/w2k) works except XP.
4) The VPN server may not be able to get IP from DHCP for the VPN
client. So, you may want to re-configure VPN host networking settings.
For XP pro VPN host, go to the Properties of the VPN>Network, check
Specify TCP/IP address and Allow calling computer to specify its own
IP address, and uncheck Assign TCP/IP addresses automatically using
DHCP.
5) Make sure other secure software blocks your access, for example, if
you use Norton secure software, you may need to add the remote
client's IP so that the client can access.
Jeffrey Randow (Windows Net. & Smart Display MVP)
(e-mail address removed)
Please post all responses to the newsgroups for the benefit
of all USENET users. Messages sent via email may or may not
be answered depending on time availability....
Remote Networking Technology Support Site -
http://www.remotenetworktechnology.com
Smart Display Support -
http://www.smartdisplays.net
Windows XP Expert Zone -
http://www.microsoft.com/windowsxp/expertzone