Test ports if they're open?

[EW67]

Hi! 

I'm using Kubuntu x64 13.04 and I just installed the last Qbittorrent version, from PPA repository.

I've set the incoming and DHT ports to 50000 and 50001.
How can I test, if they're actually open?

TIA! 

[Peter]

Just Google for "check for open ports".
(Because services come and go, so there is no definite place.)

First hit for me: http://www.yougetsignal.com/tools/open-ports/
But please note, sometimes these tools fail. They did for me, when I used an openWRT firmware on my router.
They would say it's blocked, but every port I opened worked just fine (with applications).
(If you use UPnP, make sure qBittorrent is running when you are running the checks.)

[EW67]

THANKS shiki for your help!!! 

Yes, I know about these web based services, but when I tried them at past, I had not the best experience.
Most of them are problematic.

I wish Qbittorrent had an inside the application tool, that can check the succesfully established communications with the outside world.
I think, I'll post for it, at wishlist. 

[loki]

Most of these in-app tools just resolve the same sites... so same problem really. Besides the yellow/green icon which signals if you are connectable or not.

[Peter]

The in-built uTorrent check works just the same.
Besides, this would need a VPS/Server to perform the checks. While uTorrent sold even their souls, we are a FOSS project.
(Holy crap. Did you guys see the latest version? Yesterday I had to install a client quick and I went for uTorrent.
The 60% of the interface was literally ADS. Yeah I know you can turn them off but damn. And casual people use this every day. wow.)

[Nemo]

I test my port with this site, if needed: www.canyouseeme.org.

Oftopic:
Yes it gets more bloated with every version it seems, Even if you can turn them off thats not the point, the point is that there are ads already build in starting from the install process till the main screen. The main crowd probably uses it with the ads anyway.

[EW67]

Indeed I dislike too, mi-torrent.
I install open source ONLY, software at my system. 

Anyway, there are a couple of other projects that already has this feature (port check), notably Azureus and Transmission.
KTorrent too, has this feature well hidden under the surface. One has to activate the log add-on and check there fow a while, in order to confirm if it's accepting connections from outside world (Authentication(S) to 99.999.99.99 : ok).