Install shorewall-doc by entering the following commands in the terminal:
sudo apt update sudo apt install shorewall-doc
Description:
documentation for Shoreline Firewall (Shorewall)
Shorewall is an iptables based firewall that can be used on a dedicated firewall system, a multi-function masquerade gateway/server or on a standalone Linux system. . This package contains the shorewall HTML documentation.
Homepage: http://www.shorewall.net
Version: 5.1.12.1-1
Section: universe/net