I started my career doing low-level TCP/IP stuff and always found Comer's books more readable and more coherent than Stevens, which I'm not especially a fan of.
I'd second everyone else's recommendation that you just start hacking on an embeddable TCP/IP stack. It's not even hard to build one from scratch once you get over the reading/writing ethernet frames hurdle (which is just a library integration challenge).
Not really a full overview but a nice intro that covers much of what is done day to day, maybe most of it for a basic client or straightforward low capacity server:
https://www.amazon.com/Internetworking-TCP-IP-One-6th/dp/013...
I'd second everyone else's recommendation that you just start hacking on an embeddable TCP/IP stack. It's not even hard to build one from scratch once you get over the reading/writing ethernet frames hurdle (which is just a library integration challenge).