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ER605-Standalone: Unable to connect to L2TP VPN from Windows 11 machine in

ER605-Standalone: Unable to connect to L2TP VPN from Windows 11 machine in

ER605-Standalone: Unable to connect to L2TP VPN from Windows 11 machine in
ER605-Standalone: Unable to connect to L2TP VPN from Windows 11 machine in
a week ago - last edited Wednesday
Tags: #VPN #WAN Setup #L2TP
Model: ER605 (TL-R605)  
Hardware Version: V2
Firmware Version: 2.2.6 Build 20240718 Rel.82712

Hello! I am having difficulties setting up, and connecting to, a L2TP VPN on my ER605 in Standalone mode. My goal is to simply access my home network from the internet. I have gone through the setup of the VPN server on the router, and when trying to connect, I am receving a Windows 789 error:

The L2TP connection attempt failed because the security layer encountered a processing error during initial negotiations with the remote computer.

 

I have tried the steps in the following resources without any luck:

How to establish an L2TP Server by Omada Gateway in Standalone mode | TP-Link

How to configure a L2TP Server on TP-Link Router

Why my Windows PC cannot connect to TP-Link L2TP VPN server?

 

I have tried the following on the client side:

- Disable Windows firewall

- Ensure VPN-related services are started

- Add Regsitry entries

- Remove and re-add the VPN configuration

- Remove and re-add the VPN driver in Device Manager

 

Can someone help me understand what I am missing? I have tried simplifying the PSK, so that does not seem to be the issue.

 

Network info

LAN: 192.168.5.1

DHCP range: 192.168.5.100 - 192.168.5.254

VPN IP Pool: 192.168.5.90 - 192.168.5.95

 

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#1
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2 Accepted Solutions
Re:ER605-Standalone: Unable to connect to L2TP VPN from Windows 11 machine in-Solution
a week ago - last edited Wednesday

Hi @SleipOdin 

Thanks for posting in our business forum.

What is your WAN IP? Do you have a screenshot of it on the WAN status?

VPN commonly refers to the VPN server that has a public IP address. The WAN IP on the router is displayed as a public one.

You cannot bypass two NATs. You are required to get a public IP on the router in this case which is the ER605.

 

If you don't have one, contact your ISP. IPv4 is not free in most regions and countries.

 

And the security layer issue could be caused by an update from the Windows KB. You might try other devices and see if they work for the VPN connection.

 

Please mosaic your sensitive information. Here is a list of information considered sensitive:

1. Public IP address on your WAN if your WAN is.

2. Real MAC address of your device.

3. Your personal information including address, domain name, and credentials.

For troubleshooting purposes, when a WAN IP is needed, please leave some values visible for identification.

Best Regards! If you are new to the forum, please read: Howto - A Guide to Use Forum Effectively. Read Before You Post. Look for a model? Search your model NOW Official and Beta firmware. NEW features! Subscribe for the latest update! ☛Download Beta Here☚ ☛ ★ Configuration Guide ★ ☚ ☛ ★ Knowledge Base ★ ☚ ☛ ★ Troubleshooting ★ ☚ ● Be kind and nice. ● Stay on the topic. ● Post details. ● Search first. ● Please don't take it for granted. ● No email confidentiality should be violated. ● S/N, MAC, and your true public IP should be mosaiced.
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#2
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Re:ER605-Standalone: Unable to connect to L2TP VPN from Windows 11 machine in-Solution
Wednesday - last edited Wednesday

  @Clive_A I'm happy to report that this was in fact the issue: NAT was still turned on at the modem level. I am now able to get to the ER605 via the public IP. Thanks again!

Recommended Solution
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#4
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3 Reply
Re:ER605-Standalone: Unable to connect to L2TP VPN from Windows 11 machine in-Solution
a week ago - last edited Wednesday

Hi @SleipOdin 

Thanks for posting in our business forum.

What is your WAN IP? Do you have a screenshot of it on the WAN status?

VPN commonly refers to the VPN server that has a public IP address. The WAN IP on the router is displayed as a public one.

You cannot bypass two NATs. You are required to get a public IP on the router in this case which is the ER605.

 

If you don't have one, contact your ISP. IPv4 is not free in most regions and countries.

 

And the security layer issue could be caused by an update from the Windows KB. You might try other devices and see if they work for the VPN connection.

 

Please mosaic your sensitive information. Here is a list of information considered sensitive:

1. Public IP address on your WAN if your WAN is.

2. Real MAC address of your device.

3. Your personal information including address, domain name, and credentials.

For troubleshooting purposes, when a WAN IP is needed, please leave some values visible for identification.

Best Regards! If you are new to the forum, please read: Howto - A Guide to Use Forum Effectively. Read Before You Post. Look for a model? Search your model NOW Official and Beta firmware. NEW features! Subscribe for the latest update! ☛Download Beta Here☚ ☛ ★ Configuration Guide ★ ☚ ☛ ★ Knowledge Base ★ ☚ ☛ ★ Troubleshooting ★ ☚ ● Be kind and nice. ● Stay on the topic. ● Post details. ● Search first. ● Please don't take it for granted. ● No email confidentiality should be violated. ● S/N, MAC, and your true public IP should be mosaiced.
Recommended Solution
  1  
  1  
#2
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Re:ER605-Standalone: Unable to connect to L2TP VPN from Windows 11 machine in
a week ago

Hey there @Clive_A, thanks for the response! I am away from the home network for the next few days, but I can adjust some settings when I return.

 

In the WAN status, it shows a private IP from my ISP (e.g., 192.168.0.2), which sounds like where the issue resides. Would Windows still throw an error at the security layer in that situation, rather than just not being able to find the destination?

 

Regardless though, I'll try some other devices to see if I can come up with new information. I did see a bad Windows KB back in early 2022 that hosed VPN connections, but my updates should be way past that.

 

Cheers!

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#3
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Re:ER605-Standalone: Unable to connect to L2TP VPN from Windows 11 machine in-Solution
Wednesday - last edited Wednesday

  @Clive_A I'm happy to report that this was in fact the issue: NAT was still turned on at the modem level. I am now able to get to the ER605 via the public IP. Thanks again!

Recommended Solution
  1  
  1  
#4
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Helpful: 0

Views: 163

Replies: 3

Tags

VPN WAN Setup
L2TP
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