Windows 10 VPN authefication problem, CHAPv2 is on

clernoc · 08 Feb 2016

Hi win 10 gurus, I think you all heard about Windows 10 authentication problems with VPN. The only solution which works for at least 2-3 people, which I found in the Internet was to check that MS-CHAP is on in properties of my VPN connection. I checked and it is on, I also tried to check every sort of variations of CHAP/no CHAP and strength of security encryption. Nothing works. In my case there is one interesting details, it worked fine in windows 8.1 and Windows 10 which was installed on W8.1 via upgrade. Then I installed W7, VPN worked there but W7 have some issues with routing of http requests when VPN is on, so I decided to go back to W10. To my big and very unpleasant surprise I found that W10 can't connect to VPN which previously worked fine. It says classical: "The remote connection was denied because the user name and password combination you provided is not recognized, or the selected authentication protocol is not permitted on the remote access server"

Does anyone here have any actual working solution for this problem besides checking MS-CHAPv2? Some people say it is caused by wrong format of how W10 sends authentication data, but I can't understand how it worked for a couple of months ago, until I decided to reinstall system...

bro67 · 09 Feb 2016

Looks like it has been known since 2012 that MS-CHAPv2 has been a huge security risk and they finally shut the problem down with Windows 10, by removing that feature. Microsoft Security Advisory 2743314 You can go through all of the other Security advisories if you wish. Security Advisories and Bulletins

It all depends on how the VPN server is set up. The Software Engineers have royally screwed up the networking part of Windows 10 in the latest rollout. You are the first one to mention this about VPN being an issue.

I just did a quick search. Oh, it is a major PITA that goes back to November. I do love the Microsoft employee's reply to someone on Microsoft's Social.technet board. It is about as canned of a response as you can get. "Thank you for your question.

By this issue, we could refer to the following steps to troubleshoot:

1.Use the build-in VPN to check if it work
2.Then please configure the software in compatibility mode to check if it could be run
3.Contact the vendor to check Aventail could be run on the build 10596
4.Rebuild Windows profile or do a clean boot to check if the issue persist

Best Regard,"

Their last reply was to contact the manufacturer of the Firewall/VPN Appliance, because it is typical Microsoft kicking the can down the road.