Registry setting to increase PPTP VPN Connection Timeout?

Any chance you are using an SBC Internet connection ? If so there is a known issue with VPN 619 errors. To resolve un-install the SBC support tool software. Just a thought.

Nope, not an SBC connection... I have no extra software from my ISP. I have both Nortel and Cisco VPN clients for other VPNs but those are both IPsec so I doubt they conflict. Some Googling shows a lot of different possible causes for 619s, so since even when the connection works it's somewhat slow to connect I figured I'd try this one thing first before trying to check a lot of things which probably won't solve the problem. Thanks for the thought, though.

It was just a thought. I don't know how you can change it on the windows client. You can however change it on the Cisco client. It is called "Peer response timeout ". Are you having similar problem with the Cisco client?

No, no such problems with the Cisco client.

If you are really 'keen' you may be able to locate the parameter you want, though I am doubtful this will repair.
-It should be located in
HKLM\system\currentcontrolset\control\class\
-However when you get to this point, each network adapter real or virtual (such as VPN), current or deleted, as well as some other physical devices, is represented here by a HEX #{4D36E........}.
-Highlight the Class key/folder and do a search (Ctrl+F), in the Data field, for "WAN Miniport (PPTP)", without the quotes
-Pressing F3 will search for the next key containing WAN Mini..... Run until you have checked all of the keys. It usually is the first one but make sure. The proper key will have about 20-30 registry keys/options listed which are obviously for your VPN connection
-Try tinkering with these keys. I am not sure if what you want even exists but TCPConectTimeout might do it
-The same keys exist in ControlSet001, ControlSet002, etc., but usually when making TCP/IP changes you do so under the CurrentControlSet

Note: Making changes to the registry can make your system un-stable or unbootable. If you are not familiar with making changes you should not do so. You should back up the registry and or keys to which you are making changes before starting. Instructions on dong so can be found at:
http://support.microsoft.com/kb/322756

Please do not consider this a "known tweak" just a test solution.

Thanks for the suggestion... I actually did something similar before asking the question (actually I found the WAN Miniport (PPTP) GUID and searched the registry for that) but never finished looking at all occurrances, figuring that a) possibly someone here might just know already,  and  b) that it might be a single value for all connections and not one specific to each driver, and c) MS likes to define registry keys which usually work with the default value and which aren't actually explicitly in the registry unless someone needs to add them. If noone else has an answer I'll go back to the registry search approach. Last resort is probably to spy on all registry lookups when I am connecting... ugh.

I am more convinced than ever that extending the timeout has a chance of working, based on some things I've observed (among them, I was able to connect successfully from another machine on my network last night but today it too times out).

But just to make my life more interesting <g> I realize that with my primary machine (a laptop) the connection is failing a bit differently since yesterday and I have probably introduced a different problem with all my troubleshooting, or maybe due to the fact yesterday I needed for completely unrelated reasons to upgrade my Cisco VPN client. I've just done a system restore to go back two days, to hopefully resolve that problem, but I may not know until later today whether it worked.

I'll try adjusting the MTU, but my net connection is excellent and the other end seems to be also, so I tend to doubt that's the problem.

I tracked down the source of the problem that cropped up yesterday, where I couldn't connect to the PPTP VPN at all, ever. The culprit was the stateful firewall in the Cisco VPN. If the firewall in Cisco is on, the PPTP VPN will never connect, with error 619 every time. Turn the firewall off, and I can easily connect (at the moment). So I am back to the original situation for which I posted this question, whereby sometimes the PPTP VPN connects and at other times of the day it times out.

I'd play with the MTU. Only takes a few minutes to do one test at 1300. Not suggesting it is only an issue with poor connections, but the packet formation does vary from location to location and has quite an impact on VPN's.

Unfortunately I did not realize in a timely fashion that this was going to be closed, forced closure is new to me. I had meant to get back to this to label it "no answer" or whatever the proper disposition is. I apologize.

The "accepted answer" is meaningless. MTU made no difference at all and didn't actually even address the specific question asked.

I found the device driver involved, tried all its registry entries, no change. I used a registry spy to look for every entry being accessed. Found a likely one, changed it, rebooted, there was no difference at all. Tried several related things. I could see the driver reading my changed registry values but with no difference in behavior, with detailed logging turned on I can confirm it's still killing the connection at the 30 second point.

The VPN provider has improved their system apparently because I no longer have problems connecting within the 30 second time. So it doesn't really matter to me anyway at the moment. But as far as I can tell, the proper answer to my question is "can't be done", at least on my system.