Anycast vs unicast DNS

Unicast nameservers are a single path. Anycast Cloud DNS answers from 210+ servers so lookups stay close and survive volumetric attack.

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Two NS records can still be one failure domain if both addresses live on one path. Anycast is how authority becomes a network instead of a pair of hosts.

Unicast is easy to understand and easy to flood

Resolvers send queries to a specific address. That address has a home. Congestion, maintenance and DDoS all share it.

Anycast announces the same service everywhere

Cloud DNS uses 210+ Anycast servers. Resolvers reach a nearby available path. Records do not change; reachability does.

Features still sit on top

GeoDNS, health checks and one-second TTLs are record policy. They are only useful if the nameservers are reachable. Anycast is that reachability.

You still need two NS names

Registries want more than one nameserver name even when infrastructure is shared. Follow that, then put both on Anycast.

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Frequently Asked Questions

Is Anycast the same as GeoDNS?

No. Anycast is how the nameserver is reached. GeoDNS is which application record is returned.

Can unicast be fast?

Next to the nameserver, yes. For everyone else, and during an attack, no.

Does Anycast require BYOIP?

No. BYOIP is optional when you must keep your own prefixes.