Transmission port is opened all of a sudden?

Discussion in 'Mac Apps and Mac App Store' started by an0nymity, Aug 22, 2011.

  1. an0nymity, Aug 22, 2011
    Last edited: Aug 22, 2011

    an0nymity macrumors newbie

    Jul 6, 2011
    I been using transmission for a couple months now and i've always had a closed default port, last night i read about how the port should be opened for better downloads, i couldn't be able to open any ports because i couldn't log into the router but when i checked my Transmisson preference the next day, it was opened for the first time. same default port number. does anyone know what have cause the port to suddenly open then went back to closed?
  2. schimmel macrumors member


    Oct 31, 2009
    I've experienced the same, Transmission reporting the same port open at times, and at times close. Thing is, UDP ports (which torrents use) can not be reliably checked if they are opened - this is because UDP does not support "answering" traffic, i.e you can't send a packet and get an answer back with UDP, unlike TCP.

    So the method to check if the port is open is something of an indirect test which may fail at times it seems.

    Probably though, your router supports uPNP or NAT-PMP- most support at least uPNP. uPNP automatically opens ports when it detects outbound traffic on that port, so when you've got an "open" port it might be because traffic has been initiated on that port at first by an uploading torrent.

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