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How can I test whether a port is open on a firewall?

I travel a lot and use wifi in a lot of different places (hotels, airports, etc.)

My apps don't always work and I suspect that in some instances the broadband provider is blocking some of the ports I need.

I don't need a port scanner like NMAP since that scans a target IP for listening ports. What I need is a way to figure out whether some firewall between my PC and the Internet is blocking specific UDP or TCP port ranges.
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    Carl Galt said:
    I travel a lot and use wifi in a lot of different places (hotels, airports, etc.)

    My apps don't always work and I suspect that in some instances the broadband provider is blocking some of the ports I need.

    I don't need a port scanner like NMAP since that scans a target IP for listening ports. What I need is a way to figure out whether some firewall between my PC and the Internet is blocking specific UDP or TCP port ranges.



    Firebind is a site that was designed for this purpose. They have a java app that can test any of the 65535 TCP or UDP ports to see whether there is a firewall blocking them.

    You can test a single port or a range of ports. They also have some canned tests.

    www.firebind.com
  2. Best answer selected by Carl Galt.
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