http://www.amazon.com/Cisco-Essentials-Press-Networking-Tech... (Networking) http://www.amazon.com/DNS-BIND-5th-Cricket-Liu/dp/0596100574 (DNS)

There are always the standards texts, Computer Networks by Tannenbaum and Internetworking by Radia Perlman for the theory.

Every "web developer" should read the first three chapters of the Cricket book. The profound ignorance (that many web developers have) of DNS is inexcusable:

http://www.amazon.com/DNS-BIND-5th-Cricket-Liu/dp/0596100574

Amazon shows it's actually in its 5th edition now:

http://www.amazon.com/DNS-BIND-5th-Cricket-Liu/dp/0596100574