Ports Keep Opening & Closing

[Philosophize]

This is a very odd problem. I doubt it's caused by Transmission in any way, but it only affects Transmission (that I can notice). Also, since it involves ports, I'm not sure where else people might know enough to even begin to have a suggestion.

Anyway, Transmission's port status is constantly "unable to check port status." Since I'm having trouble downloading, I look around for discussion and solutions. I find that there is a problem with how Transmission checks, but it's not necessarily a real port problem. So I check port status online: CanYouSeeMe and YouGetSignal. What I find is that the ports keep opening and closing. Sometimes it seems as if the act of checking causes the port to open; other times, I keep checking and checking but it remains closed.

I've tried using different port numbers. I've tried connecting directly into the cable modem (usually I connect via AirPort which acts as a bridge to the cable modem).

Oh, but that's not yet the strangest part. As part of testing, I'm using 50002 via wireless and 50003 via Ethernet. Both ports have been opened on the cable modem (to different IP#s) Right now I'm connected via Ethernet and have 50003 plugged into Transmission. Port 50003 comes back as closed; 50002 comes back as open. And Transmission is downloading! Well, it's downloading for the moment - in a minute or two it will stop, then after a few minutes it will start again. Ah, there it goes - it's down. Both ports come back as closed (50003: connection refused; 50002: connection time out)... whoops, after checking 50002, Transmission started again and now that port is open. Port 50003 is closed.

So if I'm connected via Ethernet and using port 50003, Transmission only works if port 50002 is open to a different IP# ...and that port keeps opening and closing. If I'm connected via wireless, I have the same problem but then I really am on port 50002 - but my speed is lower and the port is open less.

I just can't wrap my head around this. I don't know where to begin to look for a solution. Yes, I've power-cycled everything. My current situation is actually an improvement; yesterday I wasn't downloading at all (but I also wasn't checking all of this yet). I'm so confused...

The only thing that has changed on my end between the time when everything worked and when everything stopped was that I used Terminal to flush my DNS cache. I can almost imagine that interfering with connecting to certain trackers, but that doesn't impact ports in any way, does it?

Update: after trying different searches, the most similar problems I've seen discussed involves VPNs constantly starting and stopping. The reason is because the VPN can't handle heavy traffic loads and the solution is to throttle the traffic. I tried that, just in case my problem was similar, but it didn't help. I don't think that my "on" state lasted any longer, but it kept switching between on and off as it did when the traffic isn't throttled.

[Philosophize]

Update #2: I am now finding the same behavior on a completely different network. Same cable modem/router brand, but different IP#, different internal network setup, etc. Transmission running on a different machine, however, seems to be running fine - no starting/stopping.

So, if it's not Transmission, it must be something internal to my computer? What on earth could cause something like this?

I forgot to add earlier that I've tried Transmission 1.11, 1.2, and 1.22 and had the same behavior on this laptop. So, again, it sounds like it could be something in my settings somewhere. I'm back to wondering if flushing the DNS cache was the cause, but I still can't think of a reason why that would cause a problem like this.

[blzb]

hi

any luck resolving this? i seem to have same issue.

port is open. port is open. port is closed. port is open. port is closed. port is open. port is closed. port is closed. port is open. port is closed. port is closed. port is open.

quitting and re-launching transmission often fixes the problem.

help?

[Philosophize]

It seemed to go away on its own. I didn't do anything to "fix" the problem... it just eventually stopped.

[wosk]

I'm on a macbook C2D connected directly via ethernet to a 100/100 line. I've got the same trouble as you, usually it goes away just by waiting, sometimes it doesn't. If it does go away, it comes back sooner or later. Didn't have the trouble 3 or 4 versions ago.

If someone find a solution I'm all ears.

(latest leopard installed btw)

[wosk]

bump - Latest version transmission, same problem.

[andifall]

Yep - same problem here, on the latest nightly build . .

[igniop]

Hey there, i get the same problem. (not only in transmission)
The port keeps opening and closing. it can show the port as "open" and then when i refresh as "closed"
so frustrating!

[Ryoujin]

I'm not really sure if the information that has been provided would be helpful for the developers. Would it be possible if you guys checked the Debug, see if there's any error while the issue is going on and then paste it here to help tracking the issue?

For more information: http://forum.transmissionbt.com/viewtop ... f=4&t=3274

[bigchina]

I have the same problem.. I've had to move to Vuze (ugh) temporarily because I never know if my port is going to be opened or closed with Transmission. It's almost as if it's random whether or not the port is going to be open or closed. I've tried using different ports, turning off UPnP, toggling automatic mapping..., nothing seems to affect it. I really hope this issue is fixed or at least addressed so I can go back to Transmission.

I took a little video to show the problem:

http://tinypic.com/player.php?v=2yu0t2h&s=5

[Lutin]

Same problem here with version 1.71. Besides, Transmission often crashes or freezes when I check and uncheck the Automatically map port button.
I haven't been able to connect to any peer in the last few days. I use a direct ethernet connection (no router) and firewall is off.

[livings124]

If it's crashing please supply a crash log and console output.

[Jordan]

Same problem here with version 1.71. Besides, Transmission often crashes or freezes when I check and uncheck the Automatically map port button.
I haven't been able to connect to any peer in the last few days. I use a direct ethernet connection (no router) and firewall is off.

This sounds like this ticket. Lutin, does this look like the same problem to you too?

[Lutin]

I must apology. The problem is identical, but now that I have seen the ticket I am not quite sure which version was crashing, 1.70 or 1.71. Probably 1.70. I returned to my stable 1.61 version for testing, but I couldn't make it work. Obviously the problem was mine. I then ran Diskwarrior and repaired permissions and things are working again with latest version (1.71). Sorry again for the false alert and thanks for your excellent software and support.

[FredFlinstone]

I've been having EXACTLY the problem illustrated in the video above with two macs (macbook and imac, both a year old) in my house for about six months, over two routers, and numerous updates of Mac OX and Transmission. (Currently OS 10.5.8 and Tr 1.73) I have no idea why the following worked. A friend who knows better told me it could not possibly be what really solved the problem. But when I BOTH used manual port forwarding AND automatic port mapping, the problem vanished. The port I use for transmission has been open ever since. When I change either of these settings, the problem reappears.