This is very not an answer to any question that you have asked, but might help you all the same. I would recommend either Linuxhomenetworking
or the Linux Quick Fix Handbook - essentially, these are the same materials (...but the web site may have had some corrections made, post publishing, and so may be a bit more up to date...) and the book is, or was, available as 'dead-tree-ware' and as a free download, in places.
Now this is heavily project focussed, in the 'Let's build a web server, what do we have to do, and what do we have to learn, in order to get there' kind of sense; I quite like this, but if you only want to look up one particular thing, it might mean that you have to leap into the middle of some subject, and you may or may not find that a problem.
If you don't like that, there are masses of tutorials around the 'net on almost anything related; a slightly more compact one is at Yolinux
which you might like (I don't think that it is as well written as the the first, but YMMV).
Anyway, these are 'general linux networking tuts', rather than a direct answer, but my guess is that if you go through a good general tut in detail, you'll be better placed. Apologies if I have got this wrong.