Important note about SSL VPN compatibility for 20.0 MR1 with EoL SFOS versions and UTM9 OS. Learn more in the release notes.

Tunnel Issues with FortiGate After Migration from Checkpoint on Sophos XGS2300

Dear Sophos Community,

I am reaching out with an issue regarding my Sophos XGS2300 firewall. We previously had a tunnel set up with Checkpoint (Site-to-Site), and everything was working smoothly. However, after we replaced the Checkpoint with a FortiGate device and configured the same tunnel, we started experiencing issues.

Sometimes the tunnel goes down, and on the FortiGate side, it shows that both phases are up. For example, yesterday the tunnel was disconnected three times, and the second phase couldn’t establish a connection. After restarting the tunnel on our side, it started working again.

This issue seems to occur only with the FortiGate device. When we use other vendors like Checkpoint or Cisco, we do not encounter any problems. Could you please help us understand what might be causing this?

Any assistance would be greatly appreciated as this is becoming quite urgent.

Thank you in advance!