Networking security and TCP/IP internals books/sites

I really prefer this book:

http://www.amazon.com/Network-Security-Architectures-Sean-Convery/dp/158705115X

It is very detailed.

Some (good and free) white paper on secure design is available here: http://cisco.com/go/safe

I would suggest to check IBM book this is great book and would help you a lot. This has TCP/IP Security related chapter also.

http://www.redbooks.ibm.com/abstracts/gg243376.html?Open

Unfortunately I don't know of many references that talk about attacks in terms of how they interact with the protocol stack. I'd imagine following mailing lists like Bugtraq will keep you on top of current vulnerabilities, but it sounds like you're looking for more of a primer.

I've been told that Hacking Exposed is a good general reference for those interested in learning about attack vectors; it's on my reading list, but I haven't got around to it yet.

Building Internet Firewalls, though fairly old, still offers an excellent overview of how to think about security when designing your network.