VPN Connection between Azure gateway and our Draytek Vigor 2927AC keeps going up and down

Question

Hello Everybody,

we are experiencing connection issues with a site-to-site tunnel between Azure Gateway and a Draytek Vigor 2927AC, we followed THIS GUIDE, the connection seems to start but after two or less minutes it starts going up and down,

Any idea or suggestion to make it work and stop the rollercoaster?

Thank you

Answer 1

@CANTARELLI Martino

Thank you for reaching out.

If I understand correctly, you have a Azure site-site VPN set up with Draytek Vigor 2927AC as the on-prem device and VPN connection is unstable and disconnects and connects frequently.

Firstly, as Draytek Vigor 2927AC is not listed in the validated devices list for Azure VPN Gateway, I can help you on best effort bases.

You can follow the steps mentioned below which can help in pin-pointing the exact issue.

• You can set-up diagnostic logging for your Azure VPN Gateway and check the IKEDiagnosticLog. The IKEDiagnosticLog table offers verbose debug logging for IKE/IPsec. This is very useful to review when troubleshooting disconnections, or failure to connect VPN scenarios.
• Additionally, you can go through this troubleshooting document if not already done so, and check whether Perfect Forward Secrecy feature is disabled as it can cause disconnection problems. (I see that this is disabled in the documentation you shared)
• If this does not help you can perform a packet capture at Azure VPN Gateway and see if you are able to observe any errors.

Hope this helps! Please let us know if you need any additional help for this issue. Thank you!

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