What is anycast, and why it makes your CDN faster
Anycast is one of those bits of networking magic that quietly makes the modern web fast. Here is what it is, explained without the networking degree.
Anycast lets many servers in many cities share a single IP address. When a visitor connects, the internet automatically routes them to the nearest one. That means lower latency, automatic failover if a location goes down, and a built-in way to spread out attacks — all without the visitor or you doing anything.
Normally, one IP address points to one server in one place. Anycast breaks that rule in a useful way: it lets the same IP address live in dozens of locations at once, and lets the internet's own routing pick the closest one for each visitor. It sounds like it shouldn't work. It's actually one of the most elegant tricks in networking.
The everyday analogy
Think of a big chain with one nationwide phone number. You dial it from anywhere, and you're automatically connected to your local branch — you didn't look up the local number, the system just routed you there. Anycast does that for servers: one address, and you reach whichever copy is nearest.
Why it makes a CDN faster
The quiet superpower: failover
Because every location shares the address, losing one isn't a disaster. The internet simply stops routing to the location that went quiet and sends visitors to the next nearest instead — usually within seconds, and without anyone editing DNS or flipping a switch. The same mechanism that makes anycast fast makes it resilient.
Anycast routes by network topology, not by a map. "Nearest" means fewest network hops, which is usually but not always the closest city. It's a detail, but it's why anycast routing and geographic routing can occasionally disagree.
Anycast lets one IP address live in many places and sends each visitor to the closest copy automatically. You get lower latency, instant failover and natural attack resistance, all for free from the visitor's point of view. It's a big part of why a good CDN feels fast no matter where you are.
See how NordicCDN does this for your site:
Mads has worked in IT — mostly hosting — since he was 16. He took an early stake in a SaaS company and helped grow it through to its acquisition by Visma, has built and run data-center networks, and served as CTO of a Danish data center. He started NordicCDN to make fast, secure infrastructure simple to use.
