This is with the new SBC 15.5.2607.1 that fixes the certificate expiration issue. I rebooted the server and when the SBC came back up, it reported Code: ERR | 20170629-085735.791 | 3CXTunnel | RESIP:TRANSPORT | 1348 | InternalTransport.cxx:148 | Could not bind to [ V4 192.168.1.100:5060 UDP flowKey=448 ] ERR | 20170629-085735.791 | 3CXTunnel | TUNL | 1348 | Bridge.cpp:165 | ** Resip exception caught while starting bridge '3CXSBC15.5.2607.1' (123456) ! Exception: Could not use port After that, the SBC service was stopped, or rather, I guess it never started successfully after the reboot. There's no reason that 5060 should be in use. I started the SBC and it worked fine. Maybe networking wasn't ready yet? Should the service be dependent on a network service? I'm changing the startup type to "Automatic (Delayed Start)" for now.