I often ask people I interview what their home network looks like and what their visions are. This often open doors to both inner motivation and thoughts you don't find elsewhere in an ordinary tech interview.
Particularly, it is discriminatory in that it penalizes people based on their home situation, both from a time and financial perspective. People with children, especially single parents, are often not in positions to actively maintain a home lab or complex home network, due to time constraints.
Others just might not have the inclination, and it doesn't say anything at all about their ability to perform the job.
Even if you're not going to take the lack of a home lab as a negative, it can throw a candidate off - candidates are very conditioned to feel that a hard no to an interview questions is going to be taken as a mark against them, and this is going to effect their ability to answer other questions as effectively.
A much better question is to ask how someone approaches learning new technologies or keeping up with the changes in technology in general. For some people that will be work related, for some it will be home labs, and is an important skill regardless of how much time you have available. People with home labs will almost universally talk about it, and you can get the same discussion with them, without risking discriminating against people that have to keep their skills sharp through other methods. It's also more likely to be directly relevant to the skills related to the job, rather than random projects that might be tech related but not relevant to the position being interviewed for.
You should focus on the things required for the job. Not what people do in their free time.
We do know that diversity increases the effectiveness and problem solving ability of a team - at worst, getting a bunch of people that have home labs is actively detrimental to this, and at best does nothing to improve it.
There's limited time available in interviews, and you're probably better suited asking relevant questions.
(And from a personal perspective, asking about home lab details would benefit me. I've got ten gig fiber throughout the house and close to a terabyte of RAM consumed by my VMs... But none of that is realistically making me a better employee)
I agree that competency testing, especially project based, is better. The only reason I'd ask about their off time is to get a sense of what they like and better getting to know what kinds of projects they might gravitate to, given the choice.
However they were reasonably promising on the test, so as part of the "getting to know you" part of the interview we went over where they got their knowledge. Home labs, ebay, second had stuff. Do I expect _everyone_ to have a home lab? fuck no. Do I explicitly ask about them? no.
I must take issue with discriminatory, the whole point of an interview is to discriminate against people who are not capable of the job role.
What you are talking about is social bias, and that frankly has nothing really to do with home labs, and a lot to do with people being arseholes.
Very few of the job functions we rely on in my space can be reasonably handled in 45 minutes. Resultantly, every interview question is indirect. We either reduce problems to what we hope are aggregate indicators (e.g. coding questions) with little to no certainty that we've correctly aggregated the skillset, use fast-search limit test questions that can spook candidates, or resort to fuzzy indicators that end up serving as pet questions.
For me, I check for things like accurate self assessment and subtle asshole cues, but largely indirectly, since everybody lies...
“Tell me about your home network” is one of the odder proxy questions I’ve seen, having spent a lot of time looking at this problem.
What I’ve recommended for years is to replace technical interviews with take home work sample tests. Those also have their downsides and have recently gotten a bad name because of how poorly many people execute them, but replacing your interview process with them almost always leads to better results in my experience.
The network was pretty tightly integrated into the boat, a mix of Seatalkng, RS485 and RS232. All connected to my PC through wifi. Sadly, my homelab suffered from saltwater exposure and high humidity. My Mikrotik router and LR wifi antenna stayed with me. Since coming back stateside I've replaced most of my gear with Azure, IFTTT, and Alexa. 3 things we didn't have access to while sailing.
In my case, the default wifi-router that came from the provider sits unplugged and idle.
Maybe it's useful for 'can this person describe something complex they worked on' with lots of places to dig into 'how much low level networking knowledge does this person have,' but a large number of my peers use the WiFi that comes with the modem from their ISP, and don't even realize they're doing everything wrong.