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Wednesday, July 27, 2011

Candidate invents wacky new traceroute method

I've run a fair number of technical interviews over the years. Most of them were uneventful and uninteresting, but there are a few outliers and jaw-droppers worth mentioning. There is an entire class of people out there who think they can just make up answers when they don't know, instead of just saying "I don't know". I have no idea why they just can't admit that they don't possess the information. I don't ask, and they wouldn't tell anyway.

I get to hear some interesting whoppers this way. One time the conversation got around to the topic of traceroute. I asked if he knew how it worked, and he answered in the affirmative. Okay, cool, so, tell me about it. How does it do what it does? His answer was "it prints one line for each hop and shows the times along the way".

Okay, that's how it shows you the route, I said, but how does it figure that out? What's it actually doing? He didn't know, but he didn't say that. Instead, he started saying that it "queried the router to get the list of routes". At that point he had basically whipped out a shovel and started digging a nice hole in which to bury himself. I wanted to see just how deep it would go, so I asked how it did router query.

After a lot of hemming and hawing with no technical content from him, I said, does it do a SNMP query or something? He said sure! So then I asked, okay, so how does it get the next hop? He said it queries the next router. I said, and after that? He said, same thing, until you get to the end. So finally, I said, gee, that means you're querying other people's routers all over the Internet. How do you get that kind of access? Wouldn't it be really expensive and complicated?

I didn't wait for a reply. He was done right then and there.

Long story short, if they lie in a technical interview and I catch them, I might well turn into a technical troll and start going along with their insanity. Sometimes I just want to get an idea what the color of the sky is in their world, and whether it includes unicorns, because it's clearly not based on our reality.