What’s a Network Interface?


I’ve been working with container networking a bunch this week. When learning about new unfamiliar stuff (like container networking / virtual ethernet devices / bridges / iptables), I often realize that I don’t fully understand something much more fundamental.

This week, that thing was: network interfaces!!

You know, when you run ifconfig and it lists devices like loeth0br0docker0wlan0, or whatever. Those.

This is a thing I thought I understood but it turns out there are at least 2 things I didn’t know about them.

I’m not going to try to give you a crisp definition, instead we’re going to make some observations, do some experiments, ask some questions, and make some guesses.

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