Install libfko-perl by entering the following commands in the terminal:
sudo apt update sudo apt install libfko-perl
Description:
FireWall KNock OPerator - Perl module
The FireWall KNock OPerator implements an authorization scheme called Single Packet Authorization (SPA), based on Netfilter and libpcap. . 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. . The authorization server passively listens for authorization packets via libpcap, so there is no service listening for network connections on the traditional port. Access to a protected service is only granted after a valid encrypted and non-replayed packet is detected. . This package provides the FKO module as a Perl interface.
Homepage: http://www.cipherdyne.com/fwknop/
Version: 2.6.9-2
Section: universe/perl