# Route 53 request routing Amazon Route 53 is a Domain Name Service (DNS) technology. With Route 53, the client requests its endpoint by looking up a well-known DNS domain name, and Route 53 returns the IP address that corresponds to the Regional endpoint(s) it determines most appropriate. This is illustrated in the following diagram. Route 53 has a long list of [routing policies](https://docs.aws.amazon.com/Route53/latest/DeveloperGuide/routing-policy.html) it uses to determine the appropriate Region. It also can do [failover routing](https://docs.aws.amazon.com/Route53/latest/DeveloperGuide/routing-policy-failover.html) to route traffic away from Regions that fail health checks. ![Route 53 request routing](http://docs.aws.amazon.com/prescriptive-guidance/latest/dynamodb-global-tables/images/guide-img/a90e395c-d4d5-48a9-a714-90406b23d110/images/ce431524-34d7-4a93-b068-7f1c78c0622d.png) With *write to any Region mode*, or if combined with the compute-layer request routing on the backend, Route 53 can be given full freedom to return the Region based on any complex internal rules, such as choosing the Region in the closest network or geographic proximity, or any other choice.  With *write to one Region* mode, you can configure Route 53 to return the currently active Region (by using ARC). If the client wants to connect to a passive Region (for example, for read operations), it could look up a different DNS name. **Note** Clients cache the IP addresses in the response from Route 53 for a time indicated by the time to live (TTL) setting on the domain name. A longer TTL extends the recovery time objective (RTO) for all clients to recognize the new endpoint. A value of 60 seconds is typical for failover use. Not all software perfectly adheres to DNS TTL expiration, and there might be multiple levels of DNS caching, such as at the operating system, virtual machine, and application.  With *write to your Region* mode, it's best to avoid Route 53 unless you're also using compute-layer request routing.