Duplicate IPs on the same network are one of those things that are never supposed to happen but they never seem to go away. Usually, they are pretty much a non-event, someone can go shout at the user who assigned a static IP to their workstation on a DHCP subnet, the snapshot VM that was just spun up can be shut down, etc.

Do you have multiple servers with the same content or purpose? Do you want every client to always take the best path to the closest one?

Anycast is for you!

DNS, the Domain Name System, has become something of a Swiss Army Knife of networking and systems engineering. One of the tools in this set determines a user's location, and then send an IP address of a nearby server that can service the request.

On the surface, this seems like a great idea. Let us dig deeper and see what it can break.

I get asked to explain networking concepts on a fairly regular basis. In-person, on slack, by e-mail, on LinkedIn, etc. I'm (almost) always happy to answer them, usually by drawing on any available surface.

That, though, is not the best way to let as many people as possible learn from my experience (read: mistakess) so I thought that this might be a better forum.

Have a question you want answered here? Hit me up on LinkedIn

Yeah, just realized I couldn't find scripts on my computer and I didn't remember what anything was named or what it did.

More Added Since, checkout my GitHub Gists

So, here are the first 2 I came across tonight: