05 - Route53

Question 1

What is Route53?

Answer 1

• Route 53 is Amazons DNS Service
• Route 53 allows you to map your domain names to
  
  • EC2 Instances
  • Load Balancers
  • S3 Buckets

Question 2

Route 53 performs three main functions

Answer 2

• Register domain names
• Route internet traffic to the resources for your domain
• Check the health of your resources
  
  • Route 53 sends automated requests over the internet to a resource, such as a web server, to verify that it’s reachable, available, and functional.

Question 3

Naked Domain & Zone Apex Records

Answer 3

• Naked Domain Name (no host names) = penn-family2.org
• Zone Apex Record = penn-family2.org

Question 4

Alias Records

Answer 4

Alias Record Details

• Created by Amazon, very similar to CNAME (.e.g you can map one domain to another)
  
  • Alias records are used to map rescue record sets in your hosted zone to elastic load balancers, CloudFront distributions, or S3 buckets that are configured as websites
  • Key Difference - A CNAME cannot be used for naked domain names (zone apex records), it must either be an A Records or an Alias
• Alias records automatically map your domain name to an Elastic Load Balancers
• Alias resource record sets can save you time because Amazon Route53 automatically recognizes changes in the record sets that the alias resource record refers to
  
  • Example: example.com -> ELB (lb-1-1234.us-east1.elb.amazonaws.com)
  • If IP address of ELB changes, Route53 automatically provides the new address for example.com without any changes to the hosted zone that contains the resource record sets for example.com
• Elastic Load Balancers only use domain names
• Alias records are similar to CNAME records, but there are some important differences:

Question 5

CNAMEs vs. Alias Records

Answer 5

CNAMEs

• Canonical Name = CNAME

Aliases

• Alias records provide a Route 53–specific extension to DNS functionality.
• Instead of an IP address or a domain name, an alias record contains a pointer to a:
  
  • CloudFront Distribution domain name: d111111abcdef8.cloudfront.net
  • Elastic Beanstalk Environment CNAME: example.elasticbeanstalk.com
  • Elastic Load balancer DNS Name: example-1.us-east-2.elb.amazonaws.com
    
    • Classic - ELB
    • Application - ALB
    • Network - NLB
  • S3 Website Endpoint: s3-website.us-east-2.amazonaws.com
  • Another Route53 record in the same zone (e.g. resource record set in this hosted zone): www.example.com
  • VPC endpoint: example.us-east-2.vpce.amazonaws.com
  • API Gateway custom regional API: d-abcde12345.execute-api.us-west-2.amazonaws.com

Question 6

IP Addresses

Answer 6

IP Addresses come in two forms: IPv4 & IPv6

• IPv4 - 32 bits, supports 4 Billion Addresses
• IPv6 - 128 bits, supports 340 undecillion addresses
  
  • AWS is fully compatible with IPv6

Question 7

What is contained in the Start of Authority Record?

Answer 7

What is contained in the Start of Authority Record?

• Specifies authoritative information about the zone
• The administrator of the zone
• Name of the server that supplied data for the zone
• How long for updates, failed zone transfers, default number for TTL on resource records, etc..
• TTL additional information
• The lower the TTL the faster updates to DNS records will be propagated throughout the network

Question 8

What are Name Server (NS) Records?

Answer 8

What are Name Server (NS) Records?

• These records indicate which name servers are authoritative for the zone / domain.
• The NS records are supplied to the domain register
• The NS records tell the top-level domain how to route traffic to you
• NS Records are primarily used if you want to break your domain into subdomains.
• Subdomains indicate you are delegating a portion of a domain name to a different group of name servers
• Thus creating NS records to point the name of the subdomain to different name servers.

Question 9

What is contained in a Resource Record Set?

Answer 9

What is contained in a Resource Record Set? - Background Material -

• Used to route traffic to your resources
• Each record set contains
  
  • Name - your domain name or your sub-domain name
  • Type - the type of resource you want traffic routed to (e.g. MX for email, A for IPv4 address, AAAA for IPv6 address)
  • Value - relates to type
    
    • MX = mail server name
    • A = IPv4 Address
    • AAAA = IPv6 Address