🎯

IP Anycast: Routing to the Nearest Instance

Medium

Free preview · 2 of 5 steps

One IP address, many servers

In traditional unicast, one IP = one server. Anycast breaks this: the same IP prefix is announced from multiple servers worldwide via BGP. The internet's routing infrastructure automatically directs each user to the nearest announcing server.

No DNS tricks, no client configuration — BGP's shortest-path selection does all the work. Cloudflare, Google DNS, and all DNS root servers rely on anycast.

Packets in motion — click to inspect:

1 / 2

Space to play/pause · ← → to step