Question

Hello!

How many simultaneous L2TPV3 connections does RUT360 support? I noticed that after enabling more than one connection, the router freezes / is unresponsive.

Thank you!

Answer 1

Hello,

  

Thank you for reaching out!

To better understand the issue, please replicate the issue, navigate to System → Administration → Troubleshoot and generate a troubleshoot file. It can be attached to the original post and will only be visible to Teltonika moderators.

It would also be appreciated if you could describe your topology. Are you following this guide?

  

Best regards,
DaumantasG

Answer 2

Hello!

The topology consists of a mesh triangle setup (due to latency reasons), where each router establishes a simple L2TPv3 tunnel (without IPSEC) to each other router's public IP address, in order to bring all their respective endpoints into the same LAN. I have added a config example for router 1 and a troubleshoot log after enabling the sixth (final) L2TPv3 tunnel on router 3 with router 2. As soon as this happens, all routers become unreachable and the previous working tunnels fail. After router 3 is powered off, routers 1 and 2 become responsive again.

Comments

Hello,

  

Your issue is not the L2TPv3 crashing, but rather the created loop.

The device logs are filled with messages:

br-lan: received packet on l2v3-OCCSIM with own address as source address

So unfortunately this topology will not work. Perhaps you could explain what your use case is, so we could recommend you a better solution.

  

Best regards,
DauamnatsG

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Hello!

Thank you for the explanation, now I understand what the real problem was.

I have added to my first post a Visio file with the "desired" network topology. A mandatory requirement for my project is that any endpoint can reach the other endpoints over a maximum of one Internet hop, due to low LTE signal strength and high latency reasons. Would any solution cover this case? Maybe by implementing static/dynamic routing?

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Hello,

  

It might be worth exploring options like OpenVPN or IPsec, which operate as VPNs, and not L2 tunnels. 

We have quite an extensive guide on OpenVPN configuration here and a smaller one for IPsec here.

If you go with OpenVPN, make sure to set it up in TUN mode and push the necessary routes if needed.

  

Let me know if you encounter any difficulties!

Best regards,
DaumantasG

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IPsec is not feasible, as all endpoints are in the same subnet and they need to talk to each other using their real IPs, not the virtual ones.

Regarding OpenVPN, the client-to-client packets have to be routed through the OpenVPN server (if I understood correctly), therefore I would automatically have 2 Internet hops between clients.

How about a hybrid solution with OpenVPN server on router A, OpenVPN clients on routers B and C (with client-to-client communication disabled) and a L2TPv3 tunnel between routers B and C? Would this also lead to a routing loop issue?

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Hello,

  

I'm not sure about your suggestion, but we also support DMVPN. If enables direct client-to-client communication. More about DMVPN's inner workings can be found in this article. A configuration example for our routers can be found here. However, at the moment I'm unable to test this configuration, so if something does not function properly, let me know and I'll research it.

  

Best regards,
DaumantasG