Is there any way to tell the Tor daemon on my computer to only pick entry nodes with specific TCP ports? It seems like our ISP has started blocking Tor communication on its usual ports (443, 9001, etc). Once it finds a node with POP3 port 110 open - things finally start working. Telnetting to port 443 or 9001 of the failing node doesn't block and expects user input as any open port would - therefore some more sophisticated blocking is taking place.
As you already wrote in your comment you can set
FascistFirewall 1 in your
torrc. Tor will then use the ports 80 and 443 for outgoing connections to the first node.