Unable to make VPN connection - Error 720

[szamkow]

Trying to set up VPN using PPTP on NT Server 4.0, SP6a for remote access by users on broadband connections, but all attempts result in Error 720 - unable to negotiate compatible protocol.

The test setup is an NT 4.0 Server connected directly (by crossover cable) to a Win 98 SE system, so there are no router issues. These show up on the Network in both machines and can communicate directly using NetBEUI or IPX/SPX, but not by VPN. I'm avoiding binding TCP/IP to File/Printer sharing for security reasons, although I did try enabling that too, with no success. So, with all three protocols enabled, it still can't find one it likes.

I've tried everything I can thing of, including the setups posted on J.Helmig's World of Windows Networking and the Microsoft notes.
Any suggestions would be appreciated.

 

[sobak]

Are both of your servers setup for the same security setting? You might start out using PAP on both sides to assist you in troubleshooting. Also make sure you are binding IPX/SPX to the RAS dialup PPTP device. You can have IPX/SPX installed on the system but if you don't enable it under the RAS device and attempt to make a connection via PPTP you will receive that error. Once you get the two systems up and running then you can enable either CHAP or MS-CHAP for your dialup security.

david e
*end users are just like computers, some you can work with...others just need a simple reBOOTing to fix their problems.*

 

[szamkow]

Thanks, Dave.

Both were set the same, but for troubleshooting, I've taken your suggestion and am using PAP.

IPX/SPX is now selected under network options for the VPN in RAS, but under bindings it does not appear to be bound to a WAN wrapper, as Net BEIU is. I've uninstalled and reinstalled the entire RAS setup (with SP6 update) and no change.

I can now make the VPN connection, but after 2 seconds it cancels and asks if I want to restablish the connection.

Any ideas?

 

[sobak]

Its been a long time that I've dealt with NT VPN's, I have an NT box setup at home and will attempt to setup what you have back to my company WAN. I'm a visual person when it comes to things I haven't worked on in a few years. Unless someone else posts a resolution to your problem I should have some ideas sometime tonight. Sorry for the delay I just want to ensure I steer you in the right direction.

david e
*end users are just like computers, some you can work with...others just need a simple reBOOTing to fix their problems.*

 

[szamkow]

Dave,

Thanks for the effort. I appreciate the time you're taking. Deployment isn't for another week, so there is no problem - yet. <g>

 

[szamkow]

Dave,

I think I've got it going, at least locally between the two systems.

I was going over the PPPLOG.TXT file and noticed that it wasn't starting IPX protocol from the client machine, even though that was selected in DUN>Servers. I uninstalled, then reinstalled IPX/SPX on the Win98 client machine and that seems to have done the trick.

Next step (when the DSL access is installed at the client) is to fight throught whatever router blocks get thrown up. <g>

Thanks again for your suggestions and your willingness to put in the effort to try this out. Its really appreciated.

Stan

 

[sobak]

Stan, just make sure you have the proper ports open for your VPN traffic, there are two of them. They are Port 47 and 1723 I believe. Keep this in mind and you shouldn’t have a problem. Let us know if you need any further assistance. Can't guarantee we have all the answers but we can get you going in the right direction.

david e
*end users are just like computers, some you can work with...others just need a simple reBOOTing to fix their problems.*