Definition
Anycast DNS is a modern DNS deployment approach that allows multiple geographically distributed servers to respond to DNS queries using the same IP addresses.
In this approach, DNS queries are routed to the geographically closest DNS server, which improves performance and resilience. Anycast DNS uses an Equal-Cost Multi-Path (ECMP) routing technique to distribute the traffic across multiple paths.
How Does Anycast Work
- A network of servers distributed in different geographical locations is set up. The servers must share the same IP address.
- Domain name queries from users are sent to the server closest to them geographically.
- If the server is active, it responds with the IP address of the requested domain.
- Upon receiving the IP address, the user’s device connects to the server hosting the domain.
- If, for some reason, the nearest server is inactive or overcrowded, the request is transferred to the next available node.
Benefits of Anycast DNS
- Protects against DDoS mitigation: You can always access DNS services because your request can be routed to another node if the current destination is overwhelmed by traffic or unavailable.
- Eliminates redundancy: Anycast DNS advertises an IP address across multiple nodes, creating backups if one node is unresponsive or overloaded.
- Anycast is easy to configure: All the Anycast DNS network servers have the same configurations, making them easy to set up.
- Improves performance: Anycast DNS routes DNS queries to the closest server to improve latency and speed.
- Scaling: The DNS network can handle a large number of requests without cases of server overload.