This book by Michael Lucas is an indespensible guide for those who are not network engineers or network administrators themselves:

Networking for System Administrators:

https://mwl.io/nonfiction/networking#n4sa

I just purchased this on the backs of the sibling comments.

I've never had an adequate understanding of networking but have found myself in so many situations where it would have saved me from embarrassment in front of clients and wasted hours in front of the terminal. I have high hopes for the book.

Seconded - this book is a must read for any software engineers that work with the internet (in my opinion)

Thanks for this recommendation, having not studied networking at university I've always struggled with it.

thank you so much for recommending. i checked the table of contents and this is really my kind of book.

This is a pretty good write up. I've taken to use a very similar scenario as part of my interview process for candidates. It's shocking how few SRE candidates I interview can walk me through a simple scenario such as troubleshooting this.

I don't even require the correct incantation of curl/openssl/dig/nslookup/nc/route/etc, I just want to see their process for breaking down the problem and searching for the fault. The most common thing that I see is changing the local DNS resolver, flushing the DNS cache, rebooting the local computer, disabling the local firewall, and then giving up.

I start with NXDOMAIN because the subdomain is not configured on Route53, then it gets progressively more weird from there. NACL blocking return traffic, apache/nginx service is just dead and systemd didn't restart it, apache/nginx is bound to 127.0.0.1:80/443, self signed cert with an invalid CommonName.

Each problem presents a jumping off point to dive deeper into different areas.