Route 53

A deep dive into Route 53 - Practical ver.

What is Amazon Route 53?

: A DNS (Domain Name Service) provided by AWS

Supported DNS record types

: The AWS docs provide detailed information, but here's a brief summary of the commonly used ones

• A record type

  • IPv4 address

• AAAA record type

  • IPv6 address

• CNAME record type

  • When a domain address points to another address

• MX record type

  • As the name suggests, mail server

• SPF record type

  • Mail related

• TXT record type

  • When queried, it returns one or more strings wrapped in "

  • Usage

    • reverse dns lookup

    • auth

      • A method to verify that the domain owner is legitimate

        1. Send an email to the domain owner

        • Authenticate by connecting a mail service (MX record type, etc.) to your domain and receiving the email

          • This method is a bit cumbersome, so the TXT record type below is used instead

        1. Have the owner enter a token in the TXT record

           • Authenticate by having them enter a value (token) you sent

             • This method is more preferred nowadays

alias

• A feature exclusive to Route 53

• Used to connect AWS services

• LBs should NOT be connected using CNAME

  • Why?

    • Because the LB domain changes constantly

    • However, this is specific to the cloud environment!

  • ALBs are composed of Instances

    • An Instance has 2 + a IPs

      • Why? Because more IPs are assigned when traffic is high

    • So multiple IPs are mapped and managed under a domain address

Why use alias?

• If you use CNAME

  • From the connecting client's perspective, when it queries for domain information, it has to ask for the final destination and then ask again!

    • Why?

      • CNAME follows chains of connections until it reaches the terminal record

        • Which is the IP

• The reason for using alias instead of CNAME

  • Convenience

    • CNAME requires multiple queries which is inconvenient, but using alias makes it simpler

      • How?

        • Since AWS services are all its own resources, Route 53 queries on your behalf and returns the final IP in a single lookup

  • Performance

    • Performance is slightly better from the client's perspective

  • Cost

    • Route 53 billing structure

      • Query cost: A record < CNAME

        • CNAME is more expensive

        • alias cost == A record

Route 53 Tips

• A single domain address can have multiple record types

  • You can add additional records to the same domain!

• If you want to add records of the same record type, you can register them as multiline

  • Don't create two separate records!