- What RFCs are useful to read if I want to learn networking well
- I heard that the best way to learn low-level programming is by rebuilding already existing programs. what high quality RFCs can I use as a guide to code-my-own <so and so program>
There are a number of problems with trying to learn networking from the RFCs. First, they're specifications, not tutorials, so they just assume that you have a lot of background that you otherwise have to infer. Second, it's very common for a protocol to have been iteratively developed over the years and so split over a number of RFCs. In some cases, people will eventually try to consolidate things into a single document or document suite, but it's a big pain to do that, so it often doesn't happen.
Finally, a lot of the foundational RFCs were written long before we had a good understanding of how to design a robust networking protocol. For example, if you just implement TCP's original rate control algorithm [RFC 793] you get a system which is very vulnerable to congestion collapse (see https://ee.lbl.gov/papers/congavoid.pdf for more). Even with a more modern specification for RCP as in RFC 9293, you kind of have to work to piece together the shape of a working system. The QUIC RFCs are better because they were written all at once, but it's still not really designed to teach you.
IMO a better place to start is TCP/IP Illustrated by W. Richard Stevens. Volume 1 really explains the protocols. Volume 2 shows how to actually implement them.
- What RFCs are useful to read if I want to learn networking well
- I heard that the best way to learn low-level programming is by rebuilding already existing programs. what high quality RFCs can I use as a guide to code-my-own <so and so program>