I've read this one,
nostarch.com
,
And I also enjoyed this one
nmap.org
Where did you guys get your networking knowledge?
Practical Packet Analysis, 3rd Edition | No Starch Press
Practical Packet Analysis, 3rd Ed. teaches you how to use Wireshark for packet capture and analysis.
And I also enjoyed this one
Nmap Network Scanning—The Official Nmap Project Guide to Network Discovery and Security Scanning
From explaining port scanning basics for novices to detailing low-level packet crafting methods used by advanced hackers, this book by Nmap's original author suits all levels of security and networking professionals.

Where did you guys get your networking knowledge?