I tried to study a bit from beej.us and I appreciated the style of teaching, but ultimately thought it wasn’t for me as it didn’t go much into depth and focused more on creating C programs. Is there some source from where I can learn in a comprehensive yet easy to understand manner the fundamentals of computer networking, at least to the extent that is relevant for selfhosting?
There’s lots of good stuff on YouTube, including from David Bombal and Jeremy Cioara. If you’re more of a listening-while driving person, years ago the Security Now podcast did a “how the internet works” series that gives a terrific overview of the TCP/IP stack (it’s from 2006, but it’s still very applicable). And if you like to read, Michael Lucas just released a “Networking for Sysadmins” book, which is excellent.