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L2TP VPN Server not work behind the ISP modem which run in bridge mode

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L2TP VPN Server not work behind the ISP modem which run in bridge mode

L2TP VPN Server not work behind the ISP modem which run in bridge mode
L2TP VPN Server not work behind the ISP modem which run in bridge mode
2024-05-29 00:27:54 - last edited 2024-05-30 23:57:50
Model: ER7206 (TL-ER7206)  
Hardware Version:
Firmware Version:

Hi everyone!

 

I configured my TP-Link VPN Router model ER7206 like this guide of the link below.
https://www.tp-link.com/jp/support/faq/2158/

 

My router is put behind an ISP modem which run in bridge mode and use PPPOE for access internet.

Everything is configured exactly like the guide and the router can be also accessed internet but L2TP VPN Server on the router is not working.

I don't know that it's neccessary to configure something such as open vpn port in ISP modem or not

 

Please give me some advice to fix this issue

Thank you!

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#1
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1 Accepted Solution
Re:L2TP VPN Server not work behind the ISP modem which run in bridge mode-Solution
2024-05-29 17:45:07 - last edited 2024-05-30 23:57:50

It could be NAT-T problem. Try this registry modification.

 

https://community.tp-link.com/en/business/forum/topic/668064?replyId=1365466

Recommended Solution
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#9
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12 Reply
Re:L2TP VPN Server not work behind the ISP modem which run in bridge mode
2024-05-29 01:00:43

Hi @philong1x86 

Thanks for posting in our business forum.

What does your WAN IP address look like on the WAN status on Omada router?

Screenshot it. If it is not a public IP address, you cannot access it even though you have an Internet connection. This is a concept of public Internet/WAN.ew

 

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 Manual ★ ☚ ● Be kind and nice. ● Stay on the topic. ● Post details. ● Search first. Don't be a lazy asker. ● 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:L2TP VPN Server not work behind the ISP modem which run in bridge mode
2024-05-29 01:15:31

  @Clive_A 

 

Thank you for your reply!

I have a dynamic public IP address as below. Because it's not static, I use dynamic dns with no-ip. I also configured it successfully in the router. Domain name can be resolved to public IP and vice versa.

 

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#3
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Re:L2TP VPN Server not work behind the ISP modem which run in bridge mode
2024-05-29 02:17:09

Hi @philong1x86 

Thanks for posting in our business forum.

philong1x86 wrote

  @Clive_A 

 

Thank you for your reply!

I have a dynamic public IP address as below. Because it's not static, I use dynamic dns with no-ip. I also configured it successfully in the router. Domain name can be resolved to public IP and vice versa.

 

 

OK. If this is the IP, it should work.

Since you have set up the server correctly, can you make sure you make a proper connection with correct parameters?

If possible, you may provide screenshots of the server config and cellphone or PC client config.

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 Manual ★ ☚ ● Be kind and nice. ● Stay on the topic. ● Post details. ● Search first. Don't be a lazy asker. ● 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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#4
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Re:L2TP VPN Server not work behind the ISP modem which run in bridge mode
2024-05-29 03:16:23 - last edited 2024-05-29 03:21:50

  @Clive_A 

 

Thank you for your reply, please confirm my configure L2TP VPN as below.
VPN IP Pool:

L2TP VPN

User

VPN Client Configure

Error

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#5
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Re:L2TP VPN Server not work behind the ISP modem which run in bridge mode
2024-05-29 03:39:22

Hi @philong1x86 

Thanks for posting in our business forum.

philong1x86 wrote

  @Clive_A 

 

Thank you for your reply, please confirm my configure L2TP VPN as below.
VPN IP Pool:

 

L2TP VPN

 

User

 

VPN Client Configure

 

Error

 

Is the preshared key 12345678?

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 Manual ★ ☚ ● Be kind and nice. ● Stay on the topic. ● Post details. ● Search first. Don't be a lazy asker. ● 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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#6
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Re:L2TP VPN Server not work behind the ISP modem which run in bridge mode
2024-05-29 04:27:08 - last edited 2024-05-29 04:27:54

  @Clive_A 

Yes, the preshared key is 12345678
The error is below

 

 

please help me to check

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#7
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Re:L2TP VPN Server not work behind the ISP modem which run in bridge mode
2024-05-29 06:21:02

Hi @philong1x86 

Thanks for posting in our business forum.

philong1x86 wrote

  @Clive_A 

Yes, the preshared key is 12345678
The error is below

 

 

please help me to check

Not sure if your Windows is the problem. Have you tried this on the iOS devices if you have any?

Windows once had a problem with the L2TP due to its system update. One of the KBs was causing something like this. Please make sure your computer is installed with the latest KB and the system is up-to-date.

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 Manual ★ ☚ ● Be kind and nice. ● Stay on the topic. ● Post details. ● Search first. Don't be a lazy asker. ● Please don't take it for granted. ● No email confidentiality should be violated. ● S/N, MAC, and your true public IP should be mosaiced.
  0  
  0  
#8
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Re:L2TP VPN Server not work behind the ISP modem which run in bridge mode-Solution
2024-05-29 17:45:07 - last edited 2024-05-30 23:57:50

It could be NAT-T problem. Try this registry modification.

 

https://community.tp-link.com/en/business/forum/topic/668064?replyId=1365466

Recommended Solution
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#9
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Re:L2TP VPN Server not work behind the ISP modem which run in bridge mode
2024-05-30 23:57:36

  @Libik

 

Thank you for your advice!

 

I have fixed it. Let me close this case. 

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#10
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Re:L2TP VPN Server not work behind the ISP modem which run in bridge mode
2024-08-04 09:08:28

  @philong1x86 

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#11
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