Version 1 (modified by charles, 12 years ago) (diff)

moved from "Why is my port closed?" to better follow wiki naming schemes

Why is my port closed?


Transmission needs an open port to communicate. You can open one manually or let transmission try to aquire one using NAT PMP or UPnP. Here's how to find out if it worked:

Open ports & forwarding


If you have an Apple Airport, or a UPnP compatible router, Transmission can map its port automatically. Most routers manufactured since 2001 have this feature.

  • Open Transmission.
  • Go to Preferences >> Network >> Ports, and check 'Forward port from router'.
  • If Transmission reports that the 'Port is open' then you have successfully port forwarded!

Forward manually through a Router

Read the documentation of your Router and/or check the instructions on the following Website:

The Port you need to forward can be set in Transmission's preferences >> Network >> Ports.

Open your local Firewall

To allow Transmission to communicate with the outside, you have to open your local firewall. Please read your OS's documentation on how to open a port on your system.

Possible Problems

  • You get the Message 'Port is closed'/'Port is Stealth' in the 'Ports' section of Transmission's preferences
    • Check your OS console (Console.App or dmesg) and look out for Transmission's output regarding UPnP
  • Downloads are slow
    • Choose another port
    • Check if someone else is using your internet connection
    • Limit your uploads


jah: shouldn't this page just read 'consult T's help file'? All the info here has either been directly copy/pasted from the help file, or slightly modified but not materially better. I see no reason to have duplication.

theCrank: Well, maybe it's a good idea to let this Page evolve a bit and replace the help file?

jah: why? isn't one of the 'guidelines' on the wiki front page to avoid duplication? frankly, there isn't much (if anything) that could be added here on this topic.

theCrank: In the help files there are no examples which help to identify the problem (like log snipplets, ...). We can use the wiki to describe the most common problems (and their symptoms?) more detailed and maybe stop some users in the forums to post the same questions over and over again.

Waldorf: Let's look at it differently: This is, by far, the most asked question. And, apparently, most of the ppl screaming for help either didn't read the help or think they did, but didn't. So, if, because of this page here, ppl can resolve their issues (even if it's just forwarding to the build-in help), I think it's worth it.