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Re^4: Proving a UDP port is closed

by davis (Vicar)
on Feb 01, 2011 at 15:11 UTC ( #885512=note: print w/ replies, xml ) Need Help??


in reply to Re^3: Proving a UDP port is closed
in thread Proving a UDP port is closed

Sorry, I realised the stupidity of what I'd said (the implied magic) fairly quickly! Yeah, grokking the "netstat -af inet" output would almost certainly work for me for both TCP and UDP listeners, but there's still something somehow... cleaner about the attempted connection method, at least in my head.


davis


Comment on Re^4: Proving a UDP port is closed
Re^5: Proving a UDP port is closed
by Anonymous Monk on Feb 01, 2011 at 15:29 UTC

    Is it possible for a listener to black-hole the port, and soak up messages (possibly acting on them) with no replies or indication that it has happened to the outside world?

    Such a case would require checking for listener processes rather than just shouting at the computer and waiting for echoes.

      Another good point. I suppose I could have "nc -lu 111" or similar running, and that might appear to be the same as "unreachable".

      I think this is nudging me down the netstat/lsof route...

      davis

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