It can depend on the position honestly. For us one of the most basic ones we've had for a while now is asking the candidate to state how many hosts are in a /24 network. Another is identifying standard ports such as DNS, RDP, SSH, SMTP, that sort of thing which is very, very basic fundamental knowledge when it comes to networking, I've seen more candidates get these wrong or straight up not know them than there should be, some of whom claimed to have 3+ years experience as network engineers. Fuck even giving them an IPV4 address and asking them to state if it's private or public has tripped a couple up