Figured I would throw this out there for people concerned about potential issues when going to Windows 10.
I recently upgraded to Windows 10 and come across a VPN connection issue that ultimately had an easy fix. While setting up a VPN to connect to my Windows RRAS server I found that Windows 10 would give me a connection error even though the VPN worked fine on my Windows 7 clients.
The fix was to go into the VPN Connection properties on the Windows 10 machine and then via the network adapters menu or through the IE properties for said VPN connection you select the “Security” tab and then change the authentication from EAP to “Allow these protocols”, make sure MS-CHAP V2 is check marked and your all set. Once your authentication settings are adjusted Windows 10 should connect to your RRAS server without issue.
Note: I have also had instances where I need to change the VPN type to PPTP rather than the “automatically detect”

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