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For port knocking over at my old job, one of the SAs use to perform something like the following:

 echo 'blah' > tcpcat -a -p 2222 && ssh beamin@

I cannot remember the command that I am referring to as tcpcat. Does anyone know?

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up vote 7 down vote accepted

ncat may be the tool you're looking for.

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Looks like that is it! Thanks sir. Have to wait 12 minutes to award you the answer. – Belmin Fernandez Dec 26 '11 at 20:43

It may be called netcat, Lowercase nc is what the command actually is.

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