In Route53, a hosted zone is a container for managing the DNS records on a domain that uses Route53 as its DNS provider. Route53 provides some features that other DNS providers may not have, such as the ability to use Alias records for AWS resources, and configuring a private hosted zone for use with Amazon VPC.

NS Records


An NS Record indicates which name servers are authoritative for a domain. Blue Matador checks the configured NS Record for a hosted zone in Route53 against the public DNS lookup for that domain, and will notify you if they do not match.

Reasons that the configured NS record do not match the lookup results include:

  • The domain has been configured in the registrar to use different name servers
  • The hosted zone name is misspelled
  • The value in the NS record was recently changed in Route53 -- this is rare and it takes time for these changes to propagate to name servers
  • If the domain has expired, the NS response will be empty
  • If the domain has not been configured to correctly use Route53 as the DNS service, the NS response will be from another DNS service 

Alias Records


Alias records are a Route53-specific DNS feature that allows a DNS record to point to an AWS resource. They are more efficient than CNAME records when pointing at Elastic Load Balancers, static S3 websites, CloudFront distributions, Elastic Beanstalk environments, and other Route53 records. Using an Alias record over a CNAME record for these resources reduces lookup time, and Alias records recognize changes in the resource they are pointed to.

When using Route53 as your DNS service, it is always recommended to use an Alias over a CNAME record when pointing at AWS resources. Alias records can even be created for resources in different AWS accounts by following the steps here. Blue Matador will automatically find CNAME records in your hosted zones that refer to supported AWS resources (including ELBs, S3 websites, and CloudFront distributions) and recommend that you update those to Alias records. Since not all Elastic Beanstalk environments can actually be used with Alias records, we do not actively recommend changes for those records. However, you can and should still update CNAME records to Alias records for eligible Beanstalk environments.

 

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