The book TCP-IP Illustrated is the bible. You should buy it at some point. For now, find a copy online. I had a hard copy for a while, but I left it behind with my security team when I graduated. I hope it's getting good use now. Anyway, any time you have a question about a protocol, find it here, and do some Google. Together, you are unstoppable. There are two other books in the series, but this is the book that you will use the most.
"Wikipedia as a recommended resource! Filthy casual, I read the RFCs!"
Sounds good dude, hear me out. If I am trying to understand what a protocol is, how it works, what it does, I read Wikipedia and you should too. There is no reason to fight through 500 pages of arcane nonsense when it has been distilled into the perfect amount of detail. When you are working with a protocol for the first time, or just need a refresher (I basically re-read protocols every time I touch them so I don't have to rely on memory), just read the Wikipedia entry.
Helpfully, all the RFCs are listed at the bottom... It's like maybe these are supplementary resources, meant to be used together?
Skim the DNS RFC to check out what Wikipedia has to offer. Don't read the whole thing (unless you really want to), but just see that this would have been a much easier place to answer the questions you previously answered using the RFCs.
Networking is really hard, but hopefully this exposure gave you enough. The biggest takeaway you can have is using Google and RFCs effectively to solve your problems. The good news is that when it comes to network problems, someone has already seen it before and asked the question. And, as the joke goes, it is always a DNS problem.