Some ways DNS can break

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2022-01-15 18:00:03

When I first learned about it, DNS didn’t seem like it should be THAT complicated. Like, there are DNS records, they’re stored on a server, what’s the big deal?

But with DNS, reading about how it works in a textbook doesn’t prepare you for the sheer volume of different ways DNS can break your system in practice. It’s not just caching problems!

So I asked people on Twitter for example of DNS problems they’ve run into, especially DNS problems that didn’t initially appear to be DNS problems. (the popular “it’s always DNS” meme)

I’m not going to discuss how to solve or avoid any of these problems in this post, but I’ve linked to webpages discussing the problem where I could find them.

Your network requests are a little bit slower than expected, and it’s actually because your DNS resolver is slow for some reason. This might be because the resolver is under a lot of load, or it has a memory leak, or something else.