Java Socket - port knocking

Hi
I'm new here sorry if this subject was already discusssed. I was trying to find answer without result.
I have to write simle client for port knocking technique in java, and i have little problem
Port knocking daemon works fine (easy just read firewall logs) but client i sending many packets instead of one... When server is behind the firewall
To "knock" to the server I'm using quite simle command:
Socket S = new Socket(ip,port);
Dou you have any idea how to make it work. I need this client to knock only once..
Cheers,
PP5585

Thanks:) So the only way is not to allow my port knocking to have knocks kombination like:
113455 or 22334455
And if there will be knock to the same port again just ignore it.
Cheers,
Piotr

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