https://www.amazon.com/Computer-Networks-5th-Andrew-Tanenbau...

https://www.amazon.com/Computer-Networking-Top-Down-Approach...

I'm using these two. The Tanenbaum book has a 6th edition, and I think the Top Down one has some newer editions as well. Not sure if they're the best, although they do seem relatively thorough, especially Tanenbaum.

Computer Networks by Tanenbaum: http://www.amazon.com/Computer-Networks-Edition-Andrew-Tanen...

It's a classic.

If you have some time, I suggest you read http://www.amazon.com/Computer-Networks-Edition-Andrew-Tanen...

You might also want to follow a CCNA course online.

There are probably interesting intros out there, but for what it's worth, the standard text book on computer networks is Tanenbaum: http://www.amazon.com/Computer-Networks-5th-Andrew-Tanenbaum...

I haven't looked to see if every question is covered by these, but here's some standard textbooks I like:

Algorithms and Data Structures:

http://www.amazon.ca/Introduction-Algorithms-Thomas-H-Cormen...

http://www.amazon.ca/Algorithms-4th-Robert-Sedgewick/dp/0321...

Computer Architecture and Operating Systems:

http://www.amazon.ca/Computer-Architecture-Quantitative-John...

http://www.amazon.ca/Design-Implementation-FreeBSD-Operating...

Mathematics:

http://www.amazon.ca/Calculus-James-Stewart/dp/0495011606

http://www.amazon.ca/Introductory-Statistics-Prem-S-Mann/dp/...

http://www.amazon.ca/Introduction-Mathematical-Cryptography-...

Networking and Systems:

http://www.amazon.ca/Computer-Networks-5th-Andrew-Tanenbaum/...

http://www.amazon.ca/Database-Management-Systems-Raghu-Ramak...

http://www.amazon.ca/Distributed-Systems-Principles-Andrew-T...