Linux iptables Pocket Reference
Gregor N. Purdy
Burp Suite Cookbook
Sunny Wear
Absolute FreeBSD
Michael Warren Lucas
Securing DevOps
Julien Vehent
The Complete Metasploit Guide
Sagar Rahalkar
Mastering Linux Administration
Alexandru Calcatinge & Julian Balog
Mastering Linux Network Administration
Jay LaCroix
Offensive Shellcode from Scratch
Rishalin Pillay