L2TP over IPSec Stopped Working w/o Any Changes?

NSIT

Hi Guys,

I called ZyXel Support today, got a tech online for help, he says wait a minute, left and never came back while staying connected to my computer for over 20min, i wrote to him on AnyDesk, he moved the mous but never answered...Not sure if he fell asleep or something lol

Anyhow, i noticed L2TP over IPSec from Windows Client no longer works for any of my ZyWall USG20w routers..I believe these don't work wotj CHAP ver 2?

I deleted the default VPN settings and created a new one, getting the same error which are attached to this message, hoping someone can shed some light

mMontana

Hi NSIT,
no post attachments as far as i can see. Sorry

Anyway: you said

 i noticed L2TP over IPSec from Windows Client no longer works for any of my ZyWall USG20w routers

would you please try to elaborate a bit more with info your setup? The usual stuff...

• which windows version
• which firmware version of USG20W
• if your USG20W is behind a NAT or public IP configured
• If you can connect to your device from another OS (iOS/Androd)

NSIT

Hi, thank you for your reply!

I added the missing attachments
Windows version 21H2 on Remote Computer.
USG20w Firmware version is: 3.30(BDR.9) / 1.17 / 2016-11-22 10:05:22
I can connect fine with Windows 7 running as a VM

MJStar

Can you share your win10 PC's L2TP properties? Like the below screenshot of my PC.

NSIT

Hi, i believe the old ZyWall USG20w does not support CHAP v2?

I tried both CHAP v2, CHAP, or Both...No Change!

MJStar

Oh~ Have you tried PAP only?

NSIT

Even tried PAP, i can connect fine from a Win 7 client but since ver 21H2 of Windows, none of my customers can use L2TP over IPSec for VPN

NSIT

Many others having the issue...

https://docs.microsoft.com/en-us/answers/questions/337796/20h2-l2tp-vpn-connection-failure.html

NSIT

Anyone? Is this due to the fact that routers with ver 3.xx firmware behind a NAT are not compatible with Ms Chap ver2 ?

MJStar

It seems your firmware version(3.XX) is too old, it doesn't support MS-CHAP v2.

NSIT

It was working fine until Windows ver 21H2...