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Doug Comer's "Internetworking with TCP IP" volumes 1&2. Walks you through the protocol suite along with the implementation of a simple stack in C.

https://www.cs.purdue.edu/homes/comer/netbooks.html

Richard Steven's "TCP/IP Illustrated" books are the original works, Unix network programming at its finest. More advanced than Comer's book, and much more applicable. Get used, older editions if cheaper, you will be fine.

Coursera and stanford mooc helped me understand networking deeper, you might try to apply.

which ones if you could point them out please ?

https://www.coursera.org/course/comnetworks

http://networking.class.stanford.edu/

http://www.pcvr.nl/tcpip/

https://www.wireshark.org/