7. DNS, Caching and Performance Optimization

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Amazon Route 53

Records

Last edited 52 days ago by Kirtan Chavda

DNS Record Types Supported by Amazon Route 53

A (address record): To route traffic to a resource, such as a web server, using an IPv4 address in dotted decimal notation.

AAAA (IPv6 address record): To route traffic to a resource, such as a web server, using an IPv6 address in colon-separated hexadecimal format.

CNAME (canonical name record): A CNAME record maps DNS queries for the name of the current record, such as acme.example.com, to another domain (example.com or example.net) or subdomain (acme.example.com or zenith.example.org).

Alias (an Amazon Route 53-specific virtual record): Amazon Route 53 also supports alias records, which allow you to route queries to selected AWS resources, such as CloudFront distributions and Amazon S3 buckets. Aliases are similar in some ways to the CNAME record type; however, you can create an alias for the zone apex.

CAA (certification authority authorization): A CAA record specifies which certificate authorities (CAs) are allowed to issue certificates for a domain or subdomain. Creating a CAA record helps to prevent the wrong CAs from issuing certificates for your domains. A CAA record isn't a substitute for the security requirements that are specified by your certificate authority, such as the requirement to validate that you're the owner of a domain.

DS (delegation signer record): A delegation signer (DS) record refers a zone key for a delegated subdomain zone. You might create a DS record when you establish a chain of trust when you configure DNSSEC signing.

MX (mail exchange record): An MX record specifies the names of your mail servers and, if you have two or more mail servers, the priority order. Each value for an MX record contains two values, priority and domain name.

NAPTR (name authority pointer record): A Name Authority Pointer (NAPTR) is a type of record that is used by Dynamic Delegation Discovery System (DDDS) applications to convert one value to another or to replace one value with another. For example, one common use is to convert phone numbers into SIP URIs.

NS (name server record): An NS record identifies the name servers for the hosted zone.

PTR (pointer record): A PTR record maps an IP address to the corresponding domain name.

SOA (start of authority record): A start of authority (SOA) record provides information about a domain and the corresponding Amazon Route 53 hosted zone.

SPF (sender policy framework): SPF records were formerly used to verify the identity of the sender of email messages. However, we no longer recommend that you create records for which the record type is SPF.

SRV (service locator): An SRV record Value element consists of four space-separated values. The first three values are decimal numbers representing priority, weight, and port. The fourth value is a domain name. SRV records are used for accessing services, such as a service for email or communications.

TXT (text record): A TXT record contains one or more strings that are enclosed in double quotation marks ("). When you use the simple

routing policy⁠

, include all values for a domain (example.com) or subdomain (www.example.com) in the same TXT record.

Important

The DNS protocol does not allow you to create a CNAME record for the top node of a DNS namespace, also known as the zone apex. For example, if you register the DNS name example.com, the zone apex is example.com. You cannot create a CNAME record for example.com, but you can create CNAME records for www.example.com, newproduct.example.com, and so on.

In addition, if you create a CNAME record for a subdomain, you cannot create any other records for that subdomain. For example, if you create a CNAME for www.example.com, you cannot create any other records for which the value of the Name field is www.example.com.

Reference:

Supported DNS record types - Amazon Route 53⁠

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Alias Record

Alias record is a Route 53-specific record type used to map resource record sets in hosted zones to AWS resources.

Usage of Alias Records

Map resource record sets to:

Amazon Elastic Load Balancing load balancers

Amazon CloudFront distributions

AWS Elastic Beanstalk environments

Amazon S3 buckets configured as websites

API Gateway custom regional APIs and edge-optimized APIs

Amazon VPC interface endpoints

Alias points to the DNS name of the service.

TTL for Alias records for ELB, S3, or Elastic Beanstalk environments uses the service’s default.

Resolves apex / naked domain names (e.g., example.com).

Routing internet traffic to your AWS resources

You can use Amazon Route 53 to route traffic to a variety of AWS resources.

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Routing traffic to an Amazon API Gateway API by using your domain name⁠

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Routing traffic to an Amazon CloudFront distribution by using your domain name⁠

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Routing traffic to an Amazon EC2 instance⁠

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Routing traffic to an AWS App Runner service⁠

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Routing traffic to an AWS Elastic Beanstalk environment⁠

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Routing traffic to an ELB load balancer⁠

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Routing traffic to a website that is hosted in an Amazon S3 bucket⁠

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Routing traffic to an Amazon Virtual Private Cloud interface endpoint by using your domain name⁠

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Routing traffic to Amazon WorkMail⁠

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Routing traffic to other AWS resources⁠

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Creating Amazon Route 53 and Amazon Route 53 Resolver resources with AWS CloudFormation⁠

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Comparison between Alias and CNAME Records

Comparison between Alias and CNAME Records

CNAME Records

Alias Records

Route 53 charges for CNAME queries

Route 53 doesn’t charge for alias queries to AWS resources

Can't create at the top node of a DNS namespace

Can create an alias record at the zone apex

Redirects queries for a domain name regardless of record type

Follows the pointer in an alias record only when the record type also matches

Can point to any DNS record hosted anywhere

Can only point to specific AWS resources or other records in the same hosted zone

Visible in the answer section of a reply from a Route 53 DNS server

Only visible in the Route 53 console or the Route 53 API

Followed by a recursive resolver

Only followed inside Route 53

There are no rows in this table

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DNS Record Types Supported by Amazon Route 53

Important

Alias Record

Usage of Alias Records

Routing internet traffic to your AWS resources

Comparison between Alias and CNAME Records

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