I am using twisted in a GUI application to do port forwarding over an SSH connection. All the network connections of the application (database, etc...) are routed through this connection, to simplify server configuration and secure things. My first attempt was to run the reactor in the main thread, but the application was "freezing" when e.g. doing a SELECT with SQLAlchemy/psycopg2 (I guess because psycopg2 just waits for data and blocks the twisted reactor). So I put reactor.run() in a thread and it works, but I'm getting strange issues on some platforms (for example I can't connect at all on *some* OSX computers, getting a "reactor stopping" log from twisted without any further error), and I feel I'm doing the whole thing terribly wrong. So my question is, how to do proper SSH port forwarding with conch in an application that also uses the tunnels not the asynchronous way ? If running the reactor in a thread is OK, are there particular things to watch out for ?