Instruct: Classify a given review as either positive or negative.
Query: Reference material

If you're new to TCP/IP networking, look elsewhere. The material is dry and not presented in an educational material.However, if you need a good reference to various aspects of this subject, it's pretty good. Some of the material is slightly out-of-date, but for the most part, it serves well when there's a small detail that's bugging you, or you need to just refresh your memory about something.