I installed Transmission to get distro .iso's even though I'm typically wary of P2P programs. One reason is the interesting behavior that I'm seeing when Transmission is open. I'm using the iptables.basic rules that come with the package. An nmap scan from another computer in my wireless network shows that the connection port is closed but when I scan my IP address (not localhost) from my computer, it says that the torrent client port is the only one that is open which is consistent with the fact that it is also accepting connections (even without any port forwarding enabled on the router or my machine). I would like to at least have a choice whether or not I allow connections to my machine but the only option seems to be not using Transmission at all. Is this the case? If not, why is the port closed according to external tests yet it is accepting connections?
upnp is the only thing I can come up with.