Anycast DNS
DNS hosting where the same IP is announced from many physical locations. Queries route to the nearest. The reason Cloudflare and Route 53 are fast everywhere.
Anycast is a network routing trick: announce the same IP address from many physical locations, and let BGP route each query to the nearest one. For DNS, this means a global pool of identical nameservers, each handling traffic from its local region.
Cloudflare, Route 53, Google Cloud DNS, NS1, and Vercel DNS all run anycast nameservers. The hostnames like ns1.cloudflare.com map to a single IP that lives in 300+ Cloudflare cities simultaneously.
Why anycast for DNS specifically
DNS lookups are latency-sensitive. Every page load starts with a DNS query. A 100ms DNS lookup adds 100ms to every cold page request. Anycast typically gets that down to 5–20ms by ensuring the query never crosses an ocean.
Anycast also provides natural failover. If one PoP goes down, BGP routes traffic to the next-nearest one automatically, without DNS or client changes.
What anycast doesn't do
- Doesn't give you geographic responses. Anycast routes the QUERY; the answer is the same everywhere. For geographic responses you need GeoDNS.
- Doesn't replace DNSSEC. Anycast is about reachability; DNSSEC is about authenticity.
- Doesn't make your authoritative records faster to look up. The cache hit / miss behavior is the same. Anycast just means the lookup itself reaches a server quickly.
Cost
For most SaaS, anycast DNS is included free on hosted plans (Cloudflare DNS, Vercel DNS) or pennies per million queries (Route 53). Running your own anycast network requires real network engineering and would only make sense for a DNS provider, not an end user.