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I have my own Ubuntu Server. The problem is that I cannot access the server on a lot of ports from my University. I want to see on which all ports I will be able to access. Right now what I'm doing is to make apache listen on different ports in the server and then port scan from my university to see if I can access it. So far I have discovered few ports like that which I can access. Is there someway to like open all ports or make apache listen on all the ports?

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tcpdump -nnq src host <campus-external-ip> and not port ssh this solved the problem for me – Michael Nov 16 '11 at 4:34
Where are you running your Ubuntu server? Is it behind a DSL / Cable modem. Are you sure that the modem / router have their ports open or port forwarding setup? – Lord Loh. Oct 23 '12 at 3:45

Why not run tcpdump on the server and see which of the scan packets arrive? Then you can pick one where the SYN packets actually show up, and see if the path will allow the connection to complete.

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Gr8 idea, thanks! – Benjamin Jan 7 '10 at 6:32

Install the scripts available from cookbook then scan your server using nmap. that will give you exactly the outgoing firewall rules set from your connection.

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