VPN only sometimes connecting

[Agentstarks]

I have a VPN set up on my Win2k server at work and I can connect to it from home.... sometimes. It's really picky on when it will connect. Sometimes it will connect right away and I can map drives, browse the network, print, etc... most of the time though it just sits at the verifying "username and password" step. If I take my laptop to work I can connect to the vpn right away with no problems. What could be causing it to not connect right?

TIA
Jamie

 

[John Lewis]

What are you running at home (including service pack)?

Whay kind of internet connection do you have at home?

Is the server behind a firewall? If so, what?

 

[Agentstarks]

I'm running Win XP SP1. I have Time Warner Cable for my internet connection at home. The server is NAT'ted through a Netopia router, with ports 1723, 1701, 500 all pointing to the internal address of the VPN server and the router is set to allow PPTP traffic. The connection works fine sometimes and other times it just sits there. The VPN server is on a full T1 line.

 

[John Lewis]

Something is going on during the protocol negotiation stage that is causing the problem. If you let the connection try for some time you should get an error number and text that may shed some light. Can take several minutes.

I would suspect a problem with the IP address assignment. If you only have one or two client IPs established on the server for the connection, could be that they are not being properly released. If the connection is not terminated properly (sometimes even if it is), the IP address for the connection may not be released to be used by a new connection for quite some time. Sometimes even takes a day or two or a reboot. In this case increasing the pool of addresses available to the VPN server for the connection will help.

Similar problem can occur if you are obtaining the VPN IPs via DHCP and the DHCP server doesn't like something. If you are using DHCP for the addresses, try setting a static pool.

Also could be that your client is set to request an address, and that address is not being released properly. In this case, try removing the requested address from the client.

If none of those fit, next step would be to enable logging on the server side to check things out.