IP-based routing - Amazon Route 53

IP-based routing

With IP-based routing in Amazon Route 53, you can fine-tune your DNS routing by using your understanding of your network, applications, and clients to make the best DNS routing decisions for your end users. IP-based routing gives you granular control to optimize performance or reduce network costs by uploading your data to Route 53 in the form of user-IP-to-endpoint mappings.

Geolocation and latency-based routing is based on data that Route 53 collects and keeps up to date. This approach works well for the majority of customers, but IP-based routing offers you the additional ability to optimize routing based on specific knowledge of your customer base. For example, a global video content provider may want to route end users from a particular Internet Service.

Some common use cases for IP-based routing are as follows:

  • You want to route end users from certain ISPs to specific endpoints in order to optimize network transit costs or performance.

  • You want to add overrides to existing Route 53 routing types such as geolocation routing based on your knowledge of your clients' physical locations.

Managing IP ranges and associating them to a resource record set (RRSet)

For IPv4 you can use CIDR blocks between 1 and 24 bits of length inclusive, while for IPv6 you can use CIDR blocks between 1 and 48 bits of length inclusive. To define a zero bit CIDR block (0.0.0.0/0 or ::/0), use the default (“*”) location.

For DNS queries with a CIDR longer than the one specified in the CIDR collection, Route 53 will match it to the shorter CIDR. For example, if you specify 2001:0DB8::/32 as the CIDR block in your CIDR collection and a query originates from 2001:0DB8:0000:1234::/48, it will match. If, on the other hand, you specify 2001:0DB8:0000:1234::/48 in your CIDR collection and a query originates from 2001:0DB8::/32, this will not match and Route 53 will answer with the record for the default (“*”) location.

You can group sets of CIDR blocks (or IP ranges) into CIDR locations, which are in turn grouped into reusable entities called CIDR collections:

CIDR block

An IP range in CIDR notation, for example, 192.0.2.0/24 or 2001:DB8::/32.

CIDR location

A named list of CIDR blocks. For example, example-isp-seattle = [192.0.2.0/24, 203.0.113.0/22, 198.51.100.0/24, 2001:DB8::/32 ]. The blocks in a CIDR location list don't have to be adjacent or the same range.

A single location can have both IPv4 and IPv6 blocks and this location can be associated to both A and AAAA record sets respectively.

The location name is often a location by convention, but can be any string, for example Company-A.

CIDR collection

A named collection of locations. For example, mycollection = [example-isp-seattle, example-isp-tokyo].

IP-based routing resource record sets reference a location in a collection, and all resource record sets for the same record set name and type must reference the same collection. For example, if you create websites in two regions and want to direct DNS queries from two different CIDR locations to a specific website based on the originating IP addresses, then both of those locations must be listed in the same CIDR collection.

You can also share these collections across AWS accounts using AWS RAM. When you make an update, such as editing one of the IP ranges in a collection, this update will automatically apply to all the record sets associated with the collection

For information about values that you specify when you use the IP-based routing policy to create records, see the following topics: