This was surely a good book when it was written (My edition is copyright 2009).
Sloan has a very approachable writing style and the tools which are still relevant (nmap, tcpdump, netstat, etc) are handled well.
The book is simply old - there are large sections which are very out of date (Wireshark is still referred to as ethereal) and there is no discussion of doing network troubleshooting in a cloud environment.
Great book, but can’t recommend in 2023.