Found in 4 comments on Hacker News
akandiah · 2015-09-11 · Original thread
Computer Networks by Tanenbaum:

It's a classic.

olalonde · 2014-12-29 · Original thread
If you have some time, I suggest you read

You might also want to follow a CCNA course online.

maggit · 2012-11-20 · Original thread
There are probably interesting intros out there, but for what it's worth, the standard text book on computer networks is Tanenbaum:

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