VPN extremly slow Windows 11

Abo Ashkhatoyan 86

In recent times, several users within our company have reported experiencing significant issues after updating to Windows 11 with the L2TP VPN, resulting in an extremely slow connection and a black screen when attempting to use Remote Desktop Protocol (RDP). The last updated version is KB5027231. Are there any known issues or maybe can somebody advice how I can get the solution?

Kamil Liszka 285 Reputation points

2023-07-18T08:16:00.2666667+00:00

I have the same problem for a month, connection RDP via LT2P clients on windows 11 have black screen while on windows 10 clients everything works.

did you find the cause ?

edit: found info

https://petri.com/microsoft-slow-vpn-connection-windows-11/
Jamie 5 Reputation points

2023-07-22T21:28:51.1866667+00:00

Hi

I have the same issue and the issue is confined to Windows 11. The only fix I have found is to run Wireshark in the background. As crazy as it sounds it instantly fixes the issue, but then you need to run it every time you connect to the VPN. I was hoping MS would have fixed this since it was reported in May this year and nothing has happened.
Kamil Liszka 285 Reputation points

2023-07-22T21:39:30.5266667+00:00

Hi, go to services.msc -> Routing and remote access -> change "start type" to Automatic (Delayed start) and click "Start"

Establish a LT2P connection. FIXED
Alberto Royuela Heras 5 Reputation points

2023-07-24T07:26:32.6733333+00:00

well ill be damned Kamil soliution worked
Abo Ashkhatoyan 86 Reputation points

2023-07-25T07:34:08.02+00:00

Kamil thank You very much solution worked!
Jamie 5 Reputation points

2023-07-25T07:43:38.3866667+00:00

Hi, this also fixed the issue for me. Its a shame MS wasn't able to provide a fix. Thanks Kami.
Larry Kaskey 0 Reputation points

2023-07-26T14:12:18.45+00:00

Kamil's solution is like a miracle lol. I have been uninstalling updates every day for a couple of months now. This worked perfectly. Would love to know how it fixed the issue though.
Maxime Janvier 0 Reputation points

2023-08-02T16:41:54.3033333+00:00

THANK YOU KAMIL
Adrian Buchmeier 0 Reputation points

2023-08-06T18:24:32.6033333+00:00

Ja das hat bei mir auch das Problem behoben. Yes, that fixed the problem for me too.
Andrius Karpas 0 Reputation points

2023-08-13T16:28:42.0166667+00:00

@Kamil L you solution fixed my problem, thank you.
hix 0 Reputation points

2023-08-14T12:09:54.8+00:00

Kamil, dzięki - to działa :-)
Sawitree Chatsri 0 Reputation points

2023-08-17T08:02:28.3+00:00

Thanks Kamil L. It works!
Bill Kinney 5 Reputation points

2023-08-17T19:23:54.6866667+00:00

Thank you Kamil. I had this issue and was pulling my hair out. I thought it was hardware related and was about to return this brand new PC. I had VPN running on another machine just fine so I knew it was not my network.
Dan Sexton 0 Reputation points

2023-08-21T13:41:58.7666667+00:00

Same. Kamil's fix works great.
Jamie 5 Reputation points

2023-08-21T16:54:14.8133333+00:00

Will MS acknowledge the issue and apply a fix? The solution Kamil offers works great but I don't fancy instructing staff on making these changes. MS did acknowledge they broke something in May, that was nearly 4 months ago now and still without an official solution.
shaiful 0 Reputation points

2023-08-22T06:45:02.4033333+00:00

Thanks Kamil L..Its work!
Vaishnav U 0 Reputation points

2023-08-25T06:57:14.41+00:00

Kamil .It worked thank you
Murat Sevindik 0 Reputation points

2023-09-01T08:30:07.7366667+00:00

It also worked for me, thank you!
David A 0 Reputation points

2023-09-20T06:22:30.5766667+00:00

Thank you, @Kamil L , it works!
Amy Bettis 0 Reputation points

2023-09-28T10:08:22.0433333+00:00

Kamil thank you! This solution worked perfectly!
Alec Latham 0 Reputation points

2023-10-09T21:26:50.2733333+00:00

@Kamil L Thank you so much, Kamil!
Brandon Wasteneys 0 Reputation points

2023-10-11T17:44:03.14+00:00

Thank you Kamil!
Florian Dürrbaum 6 Reputation points

2023-10-16T18:53:08.32+00:00

@Kamil L Thank you very much.
Jason Robinson 1 Reputation point

2023-10-25T12:13:47.49+00:00

@Kamil L Thanks!!! You should submit this as an answer instead of a comment.
CLERGET Alexis 10 Reputation points

2023-10-27T16:07:18.1+00:00

Thanks Kamil for the solution !

This did not fix the slow internet DNS resolution on my case tho, I had to do this too to fix it :

internet options -> Connexions -> VPN -> settings -> properties -> network management -> Internet Version 4 Protocol -> use this adress for DNS Server -> favorite 1.1.1.1 / auxiliary : 8.8.8.8
R B 0 Reputation points

2023-10-30T15:10:50.77+00:00

Thank you Kamil L. I've got at least four clients with this problem. When I read the solution I was skeptical, but nothing else has worked so I tried it on one of them this morning. Fixed!
Kyle Olsen 0 Reputation points

2023-11-03T20:30:37.2966667+00:00

Got this issue today.

Kamil you are a genius
Ess G 0 Reputation points

2024-07-30T20:08:51.9466667+00:00

I figured out what my problem was. It appears the connection to a VPN through Windows uses a lot of bandwidth. I was attempting to connecting to my home VPN from a Windows 11 laptop using my cell phone as a hotspot. I thought I had more than enough bandwidth from my hotspot, but it just wasn't enough for my Windows laptop. I used my AT&T hotspot and VIOLA, I was able to connect with no problem. To let you know how much of a bandwidth hog Windows VPN is, just know that my hotspot was giving me a download speed of around 150 Mbps or higher, but after connecting to my home VPN server, it drops to about 20 Mbps.

This seems to be a flaw in how Windows is treating VPN traffic because I don't have this issue connecting to my home VPN through my Android phone.
AA AA 0 Reputation points

2025-03-05T21:17:59.3566667+00:00

I registred to microsoft acc just to say thanks to Kamil :D I spent 2 weeks figuring out this issue.

5 answers

Christoph K 45 Reputation points

2023-08-23T07:13:07.7033333+00:00

For me uninstalling the updates KB5025305 and KB5026372 didn't work out.

The solution offered by Kamil fixed the problem:

"Hi, go to services.msc -> Routing and remote access -> change "start type" to Automatic (Delayed start) and click "Start"

Establish a LT2P connection. FIXED"
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9 people found this answer helpful.
MRai 0 Reputation points

2023-11-22T21:09:44.0233333+00:00

This Services keeps stopping after few days. Any permanent solution you have? Keep in mind already done the registry trick about splitsvc....
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Amber Malooly 10 Reputation points

2023-08-24T14:49:14.9266667+00:00

The solution by Kamil fixes the problem, thank you kind sir!!
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S.Sengupta 22,361 Reputation points MVP

2023-07-15T00:34:35.3933333+00:00

Verify that your internet connection is stable and providing adequate speeds without the VPN. Run a speed test to ensure you're getting the expected bandwidth from your ISP.

Download and install the updated Network drivers to see if it improves the VPN speed.

You can try switching to a different protocol like OpenVPN or IKEv2.

Adjust MTU settings: Maximum Transmission Unit (MTU) is the size of data packets transmitted over the network. Incorrect MTU settings can affect VPN performance. You can try adjusting the MTU value for your network adapter. To do this:

a. Press Win + X and select "Windows PowerShell (Admin)" to open an elevated PowerShell window.

b. Enter the command netsh interface ipv4 show interfaces to list the available network interfaces and their indexes.

c. Identify the interface index corresponding to your active network connection.

d. Run the command netsh interface ipv4 set subinterface "INTERFACE INDEX" mtu=1400 store=persistent, replacing "INTERFACE INDEX" with the actual index number.

e. Restart your computer and test the VPN speed again to see if it improves.

Disable Windows Auto-Tuning: Windows has a feature called "Auto-Tuning" that can sometimes interfere with VPN connections and slow down speeds. You can try disabling it to see if it helps. Here's how:

a. Open an elevated Command Prompt by pressing Win + X and selecting "Command Prompt (Admin)".

b. Type the command netsh int tcp set global autotuninglevel=disabled and press Enter. c. Restart your computer and test the VPN speed.

Contact your VPN service provider: If the issue persists,
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Kenneth Gilliam 5 Reputation points

2023-08-24T19:55:28.98+00:00
Running in an AD managed domain environment on Windows 11 Pro and it did not allow for the Routing and Remote Access service to be started. KB5027231 was not available as an uninstall option in Windows updates.
Here is what I found worked instead:

Uninstall KB5029351

Restart

KB5029263 will automatically install upon restart

Uninstall KB5029263

Restart
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Jeff Uson 25 Reputation points

2023-10-17T20:39:50.3433333+00:00

its happening again with the october updates
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VPN extremly slow Windows 11

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