[mwfj]

This can be generalised. It is also one of my favorite ways of doing developer interviews. Do they have a working/in-depth knowledge of what keeps the inter webs running? So many people have never ventured out of their main competence bubble, and that bubble can be quite small (but focused, I suppose).

For all I know, they believe everything is kept together with the help of magic. I guess I don't trust people who don't have a natural urge to understand at least the most basic things of our foundations.

[hueving]

I used to thing this way before I realized it's just an arbitrary hoop you make people jump through. To you, people understanding TCP might be what you claim is a basic foundation. However, it's just about as arbitrary as asking people to explain 802.11 RTS/CTS or clos switch fabrics, which are both equally as important to delivering day-to-day network traffic. Additionally, they both can come up as things you need to understand when trying to optimize jitter/latency in sensitive local network traffic applications.

Don't judge people based on which components of networks they happened to take an interest in and dive into.

[xxpor]

Part of the "problem" is that networks (even networks that span the globe) are too reliable these days. If a developer is developing network services, all they see is an input stream and an output stream. And that's all that matters 99% of the time. But add 0.1% loss, and all hell breaks lose because people don't understand the implications and rules governing the underlying protocols.

[staticmalloc]

I learned a lot about TCP (including delayed acks), the basics of 802.11, and the basics of switching fabrics in my undergrad networking class, so I wouldn't say it's totally unrealistic for someone to talk a little about those topics, depending on the role.

[sokoloff]

On the other extreme, I've seen people ask why is that IP address divided by 16? (10.0.0.0/16)

[jacquesm]

And then you have to explain to them that it's divided by 2^16...