For years we have been using Microtik at home for a small natted internal network without any problems. The problem arose when I changed my job and I need to get from a company laptop with Windows 11 via l2tp VPN to the company office.
The L2tp server is managed by my employer. If I try the l2tp vpn from a computer that is connected to the internet via a phone provider, the vpn works.

Could you please advise me how to configure Mikrotik so that I can create an L2tp VPN from a Windows machine in natted internal network with an external L2tp server (no idea what product is used) through my Mikrotik?

Thank you very much


Jan

This is a known problem with both Windows 10 and Windows 11. It has been caused by, amongst other things, an update released by Microsoft and they have acknowledged that the problem exists (how nice of them). Please see this post on Petri about the issue.

The other thing that may be causing the issue is that you haven't made the UDP encapsulation registry change that helps resolve a lot of L2TP connection issues. Take a look at Method 5 on this ISORIVER page. It doesn't hurt to make this change regardless of your VPN connection type, ISP or network equipment so I'd say it's worth doing.

You can setup vpn inside mikrotik, add some mangle and routing rules.
After that VPN always will be online, and your pc connected to the workplace without any additional windows network settings.

But this is little hard to setup for non-advanced mikrotik user.

Thank you MickeyT and everyone who thought about the cause of my problem.
Today it was revealed, when I called the ISP again, that the problem is on ISP's side in an overly restrictive policy on FW. The L2TP VPN with Windows client via Mikrotik is already fully functional.

Thank you MickeyT and everyone who thought about the cause of my problem.
Today it was revealed, when I called the ISP again, that the problem is on ISP's side in an overly restrictive policy on FW.

Happy to help. Glad to hear that you've tracked down and, I hope, solved the problem.