Port opening problems Opensuse 11.3 KDE


Please be gentle on me if I make any mistakes in posting etiquette, I am a Linux noob.

I am trying to open ports for applications and am not sure what I am doing wrong, here is some relevant information:

  1. I am not sure if the ports are open or not. When I use the online port-checking tools for a given port I have opened, they come back as unreachable, which is what I’m basing the assumption on that they are closed.

  2. I am trying to open ports for Nicotine, Ktorrent, and Skype as well as leaving some open for other apps.

3)I have opened the ports on my router (actiontec pk5000, qwest) , same range of TCP and UDP ports listed below:

4)I have added those ports under “custom allowed rules” in the yast firewall configuration on opensuse, under the “external zone” option and it reads as follows: TCP 48192:48922 UDP 48923:48928

  1. when I check these ports using a portscanner such as: Open Port Check Tool they come up closed.

  2. running zenmap, it shows these ports open: TCP: 25,9999,48912 and UDP 111,631,and 5353
    (not sure what the 631,9999,and 5353 are). I have Ktorrent open now, it is set to use 48912, so I’m wondering if the ports dynamically open when the app is opened, and are closed otherwise?

I am trying to determine where the problem is. I just migrated to Linux, and I am confident my Router settings are correct as they are the same as I used when I was running Windows and they always came back as open.

Nicotine won’t download anything, which leads me to suspect the ports are indeed closed. KTorrent is chugging along, but is using DHT and in my experience can get good speeds even with a closed port.

Any help you can offer is greatly appreciated.

Oops, I am a bit dyslexic, the port range for TCP is 48912:48922, and it is set under CUSTOM RULES

“Closed” means that you are not running an application that is listening on that port. If the firewall were blocking access, the ports would come up “stealth” (though that might depend on how the particular scanner categorizes them).

Currently I am running Ktorrent and Thunderbird, when I check ports 25 and 49812, they both return the results “closed.”

If I turn off the firewall I get the same results. Sigh. I loathe the idea of returning to Windows.

On 02/12/2011 10:36 AM, jnemes wrote:
> If I turn off the firewall I get the same results. Sigh. I loathe the
> idea of returning to Windows.

Does the current router setup get you what you want when you run Windows?

The reason I ask, is that I’m not clear on what you want. On my network, I only
open my router to those ports that I want an outside source to be able to use to
contact an internal server. At the moment, the only one of these is SVN.

If that is not what you want, then turning off the firewall on your box opens
everything from the inside of your private network to reach the Internet as most
routers do not block connections established from inside out, and they then
allow outside in for connections established in this manner.

Both Ktorrent and Thunderbird work just fine here, but a port scan (from
outside) on my IP number would show only the SVN port open.

Thunderbird connects to an external port 25 to send email. It won’t be listening on the port itself. So of course port 25 will show as closed. For me, port 25 shows as open, because I am running sendmail as an smtp server.

If you were using Windows, and running Thunderbird, port 25 would show as closed (or as stealth). Thunderbird doesn’t listen on any ports so doesn’t open them.

I’m not a torrent user, so I don’t know the port requirements. As far as I know, it is a client that also acts as a temporary server while running. I think it announces the ports it is listening on.

At a command line, try:

netstat -at | grep LISTEN

to show which TCP ports you are listening on, and

netstat -au

to show which udp ports are active (there really isn’t a concept of “listen” for udp ports).