Unable to establish WireGuard VPN between RUTC50 and FRITZ!Box — many users affected

[omc69]

We’ve spent the past days trying to establish a stable WireGuard VPN tunnel between a Teltonika RUTC50 (latest Firmware) (client) and a AVM FRITZ!Box 7690 (latest Firmware) (server) — and it’s simply not working.

Our setup is straightforward:

• FRITZ!Box LAN: 192.168.1.0/24

• Teltonika LAN: 192.168.10.0/24

• WireGuard tunnel network: 10.8.0.0/24

• Port forwarding for UDP 51820 is configured on the FRITZ!Box side.

• We’ve generated the keys on the Teltonika side, inserted the public key into the FRITZ!Box peer configuration (as required), set proper AllowedIPs and routes on both sides, disabled NAT on the tunnel, and enabled keepalive.

The handshake never happens — the RUTC50 shows “No handshake”, and the FRITZ!Box logs stay completely silent. We’ve triple-checked firewall zones, MTU settings, routes, endpoint reachability, and NAT rules.

A quick search online reveals that many users are reporting exactly the same issue: establishing a WireGuard VPN with a FRITZ!Box as server and a Teltonika router as client seems practically impossible at the moment.

Please clarify:
– Is this a known limitation with FRITZ!Box WireGuard?
– Does the RUTC50 support the required configuration for FRITZ!Box LAN-to-LAN site-to-site VPN?
– Are there any workarounds or firmware fixes planned?

This is a major pain point for many users who rely on Teltonika routers in home-office or branch site scenarios. Any official statement or tested configuration would be appreciated.

Best,
Christian

[anon65719490]

Hello,

Thank you for reaching out.

Could you please share screenshots of both your FRITZ!Box and Teltonika WireGuard configurations?

There was a similar topic discussed recently where there was an almost identical VPN setup between a Teltonika router and a FritzBox was successfully implemented practically. You can check it here:

• FritzBox 7590 and RUT956

It might help pinpoint what’s missing in your case.

Additionally, there’s a Teltonika & FRITZ!Box WireGuard configuration example available here: FritzBox and Teltonika WireGuard Configuration example - Teltonika Networks Wiki
that may provide useful insights and instructions for your specific scenario.

Best regards,

[mumcs01]

TO give a little more context. This isn’t just FRTIZ!Box. Adding other network access to the Client literally bricks any Teltonika router and you need to factory reset. Its maddening.

NO handshake EVER happens regardless of the setup.

I tried a very simple setup with a RUTX11 and a PC Client. The minute you add any more networks to peer configurations, the UI stops responding, and it dies on save.. I gave up and went back to PepLink for the customer. I was starting to look like an idiot. Wireguard does not work on TEltonika as it stands. Which is sad.