I’ve read about 21 chapters of TCP/IP Illustrated, Volume 1: everything from ICMP and UDP to routing, multicasting, IGMP, and TCP. It’s a good experience on two levels: what I learn from the networking side of things and what I learn about coding practices, standards, and algorithms.
I just flipped through TCP/IP Illustrated, Volume 2, and it looks A LOT more hardcore. Hopefully it will teach me more about open-source software, good C code, and code walkthroughs.