This kind of interview really happens.
I spent years working on large scale graph database systems. I designed and built one of the first graph databases.
I talked to a company that said they were looking for someone to work on their graph database project. I got grilled for an hour by a guy with a heavy French accent about HTTP protocol and IP tracking. Things pretty much came to a halt when I didn’t recall how IP addresses were represented in HTTP packets.
I later pointed out to the recruiter that, in theory, they had a graph database project and that my unique contribution was graph database experience. All he could respond was that the interviewer through that everyone should know about HTTP packet format (because the French guy was working on that at the time).