fwknop-client - 2.6.10-12 main

The FireWall KNock OPerator implements an authorization scheme called
Single Packet Authorization (SPA), based on Netfilter and libpcap.
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Its main application is to protect services such as OpenSSH with
an additional layer of security in order to make the exploitation of
vulnerabilities (both 0-day and unpatched code) much more difficult.
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This is the client program responsible for accepting password input
from the user, constructing SPA packets that conform to the fwknop
packet format, and encrypting packet data.