I hope you may help me with this very strange problem. I have a Macbook with Leopard 10.5.8 installed, all firewalls deactivated, in which Transmission gives the "closed port" result in Preferences. Instead, in the other Mac, with Tiger, no firewall, Transmission has 1755 port free! I have NOT a router, but a MODEM, an Alcatel Speed Touch Home. I cannot configure it like you can do in a router. My IP is assigned by my ISP.
What could be the problem with my Macbook?
Thank you very much for your time
This is the result of Debug (I've tried more ports, also random)
2009-09-16 12:17:32 +0200 net.c:400 [Debug] Transmission: Bound socket 7 to port 52907 on 0.0.0.0
2009-09-16 12:17:32 +0200 net.c:400 [Debug] Transmission: Bound socket 8 to port 52907 on ::
2009-09-16 12:17:32 +0200 net.c:400 [Debug] Transmission: Bound socket 7 to port 52907 on 0.0.0.0
2009-09-16 12:17:32 +0200 net.c:400 [Debug] Transmission: Bound socket 8 to port 52907 on ::
2009-09-16 12:17:44 +0200 net.c:400 [Debug] Transmission: Bound socket 7 to port 1755 on 0.0.0.0
2009-09-16 12:17:44 +0200 net.c:400 [Debug] Transmission: Bound socket 8 to port 1755 on ::