Nmap Network Scanning
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SSH Mastery: OpenSSH, PuTTY, Tunnels and Keys
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Linux Advanced Routing and Traffic Control HOWTO
Gregory Maxwell & Remco Mook & Martijn Oosterhout & Paul Schroeder & Jasper Spaans & Bert Hubert
The Wireshark Field Guide
Robert Shimonski
Cyber Security and Network Security
Sabyasachi Pramanik & Debabrata Samanta & M. Vinay & Abhijit Guha
Linux Bible (10th edition)
Christopher Negus
GitHub For Dummies
Sarah Guthals & Phil Haack