Experience first and foremost. Most of the best server techs I know are not certified. They are too busy working. Some of the Cisco guys have to be in a way but that's a diff scenario. I would at least ask the following:
Explain what DNS is and how it works.
What is the difference between a layer 2 switch and a layer 3 switch?
What is the color order of 568b wiring?
Whats the difference between a hub and a switch?
What does VPN stand for and how is it used?
In Active directory, what does an OU stand for? And what is the main difference between a folder and an OU?
Where should the DNS server on a workstation point to in a Server environment running active directory.
How would you very quickly test DNS operation on a workstation?
What are a few benefits of a Domain environment?
What are the steps (from memory) to add an IP printer to a workstation. Assuming printing is direct to the printer. (make sure they choose local port instead of Network port). This usually throws beginner guys and non techs installing themselves lol.
And the one that usually gets all but the truly seasoned guys lol..... 192.168.0.31 and 192.168.0.63 arent working in a subnetted environment with a mask of .224, but 192.168.0.22 and 192.168.0.72 work fine. What could be the problem?
If they get the last one quickly then they most likely have a good solid networking background. This question is usually only answered by Cisco guys for some reason but I usually ask it anyway lol.
A decent network / server tech should really be able to answer most, if not all of those questions to be honest.
These are great questions... I need to dig my questions up for you. If you really want to find out who has knowledge a very easy way to do it is pull some random piece of equipment and ask them about it. i.e. I might pass a random fiber cable such as this 50/125 µ cable (I random have on my home desk) and ask them to identify the type of cable and connectors on the end.
If they immediately identify it as a fiber patch cable with LC connectors, they have probably worked with enterprise/corporate/Government networks. If they recognize it is aqua, which is generally multimode 50/125 µ great for SX to 550m (better than 62.5/125 good to 220m on SX)... and that this stuff can be used with LX to go further then they have a TON of experience.
And what is the main difference between a folder and an OU?
There are NO folders in AD, but there ARE Organizational Units AND Container Object Schemes. You cannot link a Group Policy Object to a Container for example... that's the major difference that comes to mind.
How would you very quickly test DNS operation on a workstation?
I am presuming you are looking for people to bring up nslookup... There is really no other tool built in that can test the various record types like SRV records etc.
https://www.technibble.com/forums/threads/server-issue.31229/ I guess if they say they can ping by name vs ping by IP they get some credit.
What is the difference between a layer 2 switch and a layer 3 switch?
Lol, generally only the firmware and/or licencing... If you get this smart-ass answer, you have a seasoned tech!
This question does not make a lot of sense:
And the one that usually gets all but the truly seasoned guys lol..... 192.168.0.31 and 192.168.0.63 arent working in a subnetted environment with a mask of .224, but 192.168.0.22 and 192.168.0.72 work fine. What could be the problem?
What mask is .224? Is that 255.255.224.0 or 255.255.255.224 ? (i.e. /19 or /27 respectively)... I am going to guess it is a /27, but technically RFC1918 sets aside 192.168.0.0/16 for private addressing and being we live in a "classless" IP world, /19 would be valid...
Presuming /27:
192.168.0.22 and 192.168.0.31 are on the same subnet (.31 is a broadcast IP not usable for a host)
192.168.0.63 actually belongs to 192.168.0.32 network-id (subnet), but it is a broadcast for that network! (NOT usable for a host)
Either way they are both on different network subnets anyway.
192.168.0.72 is pretty lonely hanging out all by himself on your 192.168.0.64 network-id (subnet). He is still unable to talk to 192.168.0.22 from the 192.168.0.0 network subnet because some tech put them both on the same Layer-2 network when they will need some Layer-3 routing tables and a Layer-3 switch or router to talk to one another. ;-)
Either way a great network tech will recognize this subnet mask and instinctively know every 32 is the next network! That .240 would be every 16 a new network... that 248 is every 8 etc. A seasoned network guru will NOT need to do any binary math, need a calculator, or any paper to figure this out. Heck a seasoned guru would look at this and know the wildcard mask as 0.0.0.31 if he were going to setup OSPF to advertise routes between a couple routers or switches ;-)