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I have an interesting problem for you.

I have a few ports that I opened up. On my router and I allowed then on my firewall too with sudo ufw allow 30999.

But still the application which would use it, for example ssh server, still can't. And if I go to an open port checker site it still says that the port is closed.

So I ran out of options. I did the usual. I restarted and stuff like that, but nothing seems to help.

This is an Kubuntu 12.04 32 Bit. updated machine. Wireless connection with a Sky Broadband router in the UK.


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Never mind.... Just found it that there was no service running behind it. So it seems that it is closed as long as there is no service behind it.

My bad. Noob. Just learning the curve. Sorry.

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The port is not 'closed', there is simply nothing listening on that port. If you tell an application (ufw, iptables, etc) to block it, it is now closed and SHOULD start timing out. No application listening? Connection refused. Blocked or closed by a firewall? Times out because it simply drops the packets, ignoring them. – UtahJarhead Apr 19 '12 at 23:04

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