Windows 11 can not work properly via PPTP/L2TP VPN connection

Question

Hi,

I got a problem that my windows 11 could not work properly when connected to my hardware VPN router.

Windows 11 could not access internal network's service via PPTP or L2TP, I tried sth as followed:

• trace route by "tracert" command worked fine, fisrt destination is the virtual IP assigned to win11, next and the final destination is the target server I traced (2 jump)
• I setup a UDP service on my server behind VPN, win11 can visit this service by udp client , seems UDP protocol worked fine.
• I can ping my internal server , ICMP seems worked fine
• I can not visit any TCP based service, like FTP, remote desktop, HTTP portal.
• windows 11 can temporary visit TCP service behind VPN if I connect to my VPN account right after a reboot, after 3-5 min, it can not visit any TCP service again.

With same connection account I tried Win 10, Win server 2019, MacOS, all of them worked fine except my win 11 mentioned above.

OS ver: windows11 21H2 22000.708
VPN server: TPLINK TL-R476G

Any solution or suggestion is highly appreciated.

Answer 1

Same over here. It took me weeks until I found this thread here. I'll wait now unitl MS makes a statement. It is truly not possible to figure out, where the bug exactly is, because there is nothing suspicious in the Events/Logs.....

Firewall: Sophos SG135

Systemconfig:

Betriebssystemname: Microsoft Windows 11 Pro
Betriebssystemversion: 10.0.22000 Nicht zutreffend Build 22000
Betriebssystemhersteller: Microsoft Corporation
Betriebssystemkonfiguration: Eigenständige Arbeitsstation
Betriebssystem-Buildtyp: Multiprocessor Free
Registrierte Organisation: Nicht zutreffend
Ursprüngliches Installationsdatum: 16.06.2022, 12:21:05
Systemstartzeit: 14.08.2022, 12:48:20
Systemhersteller: Dell Inc.
Systemmodell: Precision 5570
Systemtyp: x64-based PC
Prozessor(en): 1 Prozessor(en) installiert.
[01]: Intel64 Family 6 Model 154 Stepping 3 GenuineIntel ~2500 MHz
BIOS-Version: Dell Inc. 1.3.0, 20.04.2022
Windows-Verzeichnis: C:\Windows
System-Verzeichnis: C:\Windows\system32
Startgerät: \Device\HarddiskVolume1
Systemgebietsschema: de;Deutsch (Deutschland)
Eingabegebietsschema: de;Deutsch (Deutschland)
Zeitzone: (UTC+01:00) Amsterdam, Berlin, Bern, Rom, Stockholm, Wien
Gesamter physischer Speicher: 65.207 MB
Verfügbarer physischer Speicher: 55.827 MB
Virtueller Arbeitsspeicher: Maximale Größe: 74.935 MB
Virtueller Arbeitsspeicher: Verfügbar: 64.539 MB
Virtueller Arbeitsspeicher: Zurzeit verwendet: 10.396 MB
Auslagerungsdateipfad(e): C:\pagefile.sys
Domäne: WORKGROUP
Anmeldeserver: \PRECISION
Hotfix(es): 4 Hotfix(e) installiert.
[01]: KB5015732
[02]: KB5012170
[03]: KB5016629
[04]: KB5015898
Netzwerkkarte(n): 2 Netzwerkadapter installiert.
[01]: Intel(R) Wi-Fi 6E AX211 160MHz
Verbindungsname: WLAN
DHCP aktiviert: Ja
DHCP-Server: 192.168.178.1
IP-Adresse(n)
[01]: 192.168.178.87
[02]: Bluetooth Device (Personal Area Network)
Verbindungsname: Bluetooth-Netzwerkverbindung
Status: Medien getrennt

Answer 2

If it's any help for others. We noticed that laptops affected on our side had the Dell Optimizer running for Network.

Disabling this, fixed the issue.

Answer 3

I apologize for my ignorance for posting. This is my first time posting here. Seeing the date, my guess is this may already been resolved. I had what may be similar windows 11 issue. Try this, go to Network and Internet, advanced network setting, more network adopter options, Right click the VPN you are having issue with and select Properties, go to Security, make sure "Microsoft CHAP Version 2 (MS-CHAP v2) is enabled. Not saying this is your issue, and you may already know about this settings. I fought a similar issue and this was my fix. My Client VPN is a UDM SE and once I did this setting everything worked. Hope this helps, good luck.

Answer 4

I was using a Cisco Meraki L2TP connection and had very sluggish internet speed over client VPN. Today I finally installed Cisco Meraki Any Connect V.5.0.02, which fixed the issue.

Since May 2023, Microsoft has not made any improvements to solve VPN issues in Windows 11. I encountered this problem following the KB5026372 Windows upgrade.