troubleshooting Question

Understanding a Port Sniffer

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jdanaFlag for United States of America asked on
Software FirewallsWindows OS
2 Comments1 Solution570 ViewsLast Modified:
A buddy directed me to a slick little website application called "Shields Up."  One of the tools it offers is a port sniffer.  My network is open to port 3389 to facilitate RD.  I tested the port using Shields Up, and the utility shows it as open.  As a second test, I set up port forwarding for port 38 (a random port) on my DSL router and my internal router just as port 3389 is set up.  I then tested port 38 using Shields Up.  The application showed the port as closed.  Here's my question: What constitutes "open" for a port sniffer?  If the sniff on port 38 gets through my firewall, but port forward "listener" workstation doesn't know what to do with it, is the port still "closed"?  Or, is there another reason that this port still shows as closed in "Shields Up"?  (There are no firewall utilities running the listener workstation.)
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