Linux iptables Pocket Reference: Firewalls, NAT & Accounting (Pocket Reference (O'Reilly))

Linux Firewalls: Enhancing Security with nftables and Beyond

SSH Mastery: OpenSSH, PuTTY, Tunnels and Keys (IT Mastery Book 12)

Linux Networking Cookbook: From Asterisk to Zebra with Easy-to-Use Recipes

Linux Firewalls: Attack Detection and Response

Linux Pocket Guide: Essential Commands

Shell Scripting: How to Automate Command Line Tasks Using Bash Scripting and Shell Programming

The Hacker Playbook 3: Practical Guide To Penetration Testing

Bash Pocket Reference: Help for Power Users and Sys Admins

SSH, The Secure Shell: The Definitive Guide: The Definitive Guide

Linux Command Line and Shell Scripting Bible