Amazon Route 53 is a highly available and scalable cloud Domain Name System (DNS) web service.


What is DNS?

DNS is a service that translates human readable domain names (e.g., to an IP address (e.g.,

  • It does so by communicating with a set of Name Servers (that have their own set of database of mappings) who guide to the right Name Server that actually contains that domain name mapping.
  • Following diagram shows a typical process of resolving domain name to an IP address

DNS Query Sequence

Image courtesy of AWS


Key Features of Route 53

  • Resolver enables recursive DNS for your VPC or on-premise networks
  • Traffic Flow allows you to configure how should the traffic (targeted for your application) be routed to your application
  • Private DNS for VPC enables custom domain names for internal (to AWS) resources without exposing DNS data to the internet.
  • Health Checks and Monitoring can be done by Route 53 for your application servers.
  • Domain Registration can be done through Route 53


Key Points

  • Route 53 is highly available, and its designed & implemented in a (globally) widely distributed manner.
  • Route 53 integrates well with ELB to allow load balancing and scaling.


Routing Policies

Route 53 supports following Routing Policies

  • Simple – simply routes the traffic to specific AWS resource
  • Failover – allows Primary and Secondary target to route traffic (this is also known as Active-Passive Failover)
  • Geolocation – routes all traffic from a defined geography area to specific AWS resource
    • Geographic locations are defined at the level of Continent, Country, or at State (in case of USA).
  • Geo-proximity – enables routing of traffic based on end-user’s location against the nearest (in context) AWS resource location
    • You can adjust the proximity range of your AWS resources by using a parameter called “bias”
    • A “bias” can shrink proximity range based on negative value, or expand based on positive bias value
  • Latency – enables access to your AWS resource based on latency (between end user and target resource)
  • Multi-value Answer – allows return of multiple AWS resources (for a specific DNS query)
    • Route 53 only returns the values of healthy resources
  • Weighted – allows you to distribute traffic to different AWS resources in proportion to weights assigned to them


Amazon Route 53 currently supports the following DNS record types:

  • A (address record)
  • AAAA (IPv6 address record)
  • CNAME (canonical name record)
  • CAA (certification authority authorization)
  • MX (mail exchange record)
  • NAPTR (name authority pointer record)
  • NS (name server record)
  • PTR (pointer record)
  • SOA (start of authority record)
  • SPF (sender policy framework)
  • SRV (service locator)
  • TXT (text record)
  • Amazon Route 53 also offers alias records, which are an Amazon Route 53-specific extension to DNS.
    Alias Records allow routing traffic to AWS resources, such as ELB, CloudFront, Elastic Beanstalk , API Gateways, VPC Interface Endpoints, and Amazon S3 buckets (configured as websites).
    Alias record typically have a type of A or AAAA, but they work like a CNAME record. Using an alias record, you can map your record name ( to the DNS name for an AWS resource( Resolvers see the A or AAAA record and the IP address of the AWS resource.



Route 53 is billed for following components:

  • Hosted Zones – per each Hosted Zone
  • DNS Queries – per 1 Billion queries per month
    • Charges vary by Query type: Standard Queries, Latency Based Routing Queries, Geo DNS and Geo-proximity Queries
    • Charges are tiered – different rate for first 1 Billion queries per month, and for over first Billion queries (each month)
    • Alias -based Queries are not charged
  • Traffic Flow – per Policy Record per month
  • Health Checks – per Health Check per month
    • varies by Health Check type
    • varies by Health Checks on AWS Endpoints vs Non-AWS Endpoints
  • Route 53 Resolver – per Elastic Network Interface (ENI) hour, and per Billion queries served per month
  • Doman Name Registration / Transfers – per Domain Name


External Resources