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5cottrell@wanmon:~>telnet ntvpn1. slac.stanford.edu 1723 Trying 18.104.22.168... Connected to ntvpn1. Escape character is '^]'. Connection closed by foreign host. Exit 1 6cottrell@wanmon:~>,indicates the host is listening. If the host is not listening for a VPN connection on this port (the host may also be unreachable) then you will get:
6cottrell@wanmon:~>telnet 22.214.171.124 1723 Trying 126.96.36.199... 7cottrell@wanmon:~>
We have also been seeing problems with the VPN connection randomly disconnecting, the following gives some hints on troubleshooting hung VPN/PPTP connections and providing useful information. A more generic and complete guide to Troubleshooting PPTP on a Windows NT-based PPTP Client is also available. If the problem happens to you then the following information should be recorded and reported together with the problem to firstname.lastname@example.org.
Note the time & date of the disconnect. Is there any correlation with something you are doing at the time, e.g. a big file transfer or heavy network activity? What application were you using? What operating system are you using (e.g. Windows NT SP 5)? Does it always happen after a certain time (e.g. 20 minutes of inactivity)? After you lose the VPN connection does the green CD light on the Dial-up Networking Monitor window go out or is it still on even though the VPN session seems dead. If you go to the MSDOS window can you still ping your local gateway, can you ping the SLAC name server (188.8.131.52), can you ping 184.108.40.206 (www.stanford.edu) or 220.127.116.11 (www.sun.com)? If the green CD light is still on the Dial-up Networking Monitor window, when you ping do the TX & RX lights blink blue? After you disconnect from the VPN does the non VPN connection work OK or do you have to logoff/on first? Also are you on Pac Bell or Covad?
Below is some information (oriented to Windows NT) on how to get some of the information referred to above.
Next see if you can ping your local DSL gateway. To find the address
of your local gateway click on Start, choose Setting and click on
Control Panel, double click on Network, click on the Protocols tab,
and a Network window should appear (see below).
If the Point To Point Tunneling Protocol line appears then double click on the TCP/IP Protocol line and the Microsoft TCP/IP Properties window will appear 9see below) Note down the Default Gateway (in this example 18.104.22.168), and then go to the MSDOS window and try pinging the Default Gateway.