So is public ip accessible from both side?
That error can be caused from different situation. Probably there is an error, when negotiating between network announcements appear.
I did mention you didn`t fill up, the fields on your RUT device, where is remote subnet is not set:
And on the side of Sophos, check if there is all correct!
So generally on RUT remote subnet – means local private or real IP just to provide tunnel peer identification by addressing virtual interfaces for the booth side of the tunnel, remember IP addresses should be from the same subnet for both sides, those ip work as an identifier, like a number of doors where located some resources, mostly used when you build some dynamic routing announcement like OSPF or BGP.
You can set your tunnel with operation mode Type: Transport, in this case, you don`t need to provide IP on the tunnel sides:
Thank you for your reply. I managed to build up a site-to-site tunnel between the Teltonika RUT241 and Sophos UTM.
But the tunnel only lasts 40s and after that it changes to “Disconnected”. I tried to figure out the problem but I couldn’t find a solution.
I always get this message “received ModeCfg message when in state STATE_MAIN_I4, and we aren’t mode config client” in the Sophos UTM. After this message the connection disappear.
On the Sophos UTM the site-to-site tunnel is still connected but on the Teltonika Router is the status “Disconnected”.
I have the logs, but I can’t attach them to this reply.