VPN-Connections crashed regularly since Windows 10 Update - WeOnlyDo Discussion board

VPN-Connections crashed regularly since Windows 10 Update (wodVPN)

by gpl, Monday, December 16, 2019, 16:05 (44 days ago)

We also had this Problen in 2018, after the Rollout of Version 1803 of Windows 10: An established VPN-connection will go down, after data go through the VPN.
The solution then was to bring both station on the same version of Windows 10.

Since last week we have the same Problem at a Customer, after an update from 1903 to 1909 in Windows 10. The first Step was to check the Versions of both hosts, but in this case they are equal.

I make a lot of tests and find out, that it depents on the Packetsize and fagmentation of the Datapackets.
Example:
The VPN-Connection between two stations is established.
If I try to do a Ping over this connection with a packetsize of 1300 and activ "Not fragment"-Flag, the Ping runs without Problems. (Ping 192.168.55.6 -f -l 1300 )

If I do the same with a packetsize of 1360, the Ping answers 5 or 6 times and then connection will lost after a few seconds.

It seems, that the packet lost occur if the packetsize is near or greater than the MTU

I've found an interesting site about UDP and MTU with Windows 10, but I can't find a solution for my problem:
https://social.technet.microsoft.com/Forums/en-US/965e107e-d9b0-4240-ac3f-74797c91b476/...


Have someone the same problems? What can I do?

VPN-Connections crashed regularly since Windows 10 Update

by Jasmine, Monday, December 16, 2019, 17:50 (44 days ago) @ gpl

Hi.

For a test, if you don't forward full network, but just try to relay data to remote side, does that work, or same error happens? Of course, you can't test with ping, but you can try to redirect some known protocol to see if same problem exists.

Jasmine.

VPN-Connections crashed regularly since Windows 10 Update

by gpl, Tuesday, December 17, 2019, 16:27 (43 days ago) @ Jasmine

Hi Jasmine
This is not so easy with our program, but now I set the MTU of the physical Adapter to 1500, and the MTU of the VPN-Connection to 1400. Now it seems to work...

Hi.

For a test, if you don't forward full network, but just try to relay data to remote side, does that work, or same error happens? Of course, you can't test with ping, but you can try to redirect some known protocol to see if same problem exists.

Jasmine.