Install fwknop-apparmor-profile by entering the following commands in the terminal:
sudo apt update sudo apt install fwknop-apparmor-profile
Description:
FireWall KNock OPerator - Apparmor profile
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. . This is the apparmor profile for the FireWall KNock OPerator server.
Homepage: http://www.cipherdyne.com/fwknop/
Version: 2.6.9-2
Section: universe/admin