Route53
- DNS - Port 53
- IPv4 - 32 bit field, 4 billion addresses
- IPv6 - 128 bits
- Internet Assigned Numbers Authority - TLD
- Registrars - interNic, ICANN
- Time To Live - TTL
- SOA - Start of Authority
- NS - Name Server
- A - Address
- MX, PTR (map ip to name)
- CName - Canonical Name - map one domain name to another. Can’t be used for naked domain names (zone apex record)
- Alias - map resource record sets in your hosted zone to AWS services. (In exam, always choose Alias record?)
- ELBs never have a pre-defined IPv4 address, always resolve with DNS name
- Routing
- Simple - 1 record w/ multiple IP addresses -> return all in random order
- Weighted - allows you to split based on weights. set-id. health checks (SNS notifications, removed from DNS until healthy)
- Latency-based - route based on lowest network latency for user
- Failover - for active/passive set up. primary will need health check
- Geolocation - route based on the location of user. use cases: european customers have specific set of servers (maybe b/c configured w/ language or SLA)
- Geoproximity - Traffic Flow Only. Bias expands or shrinks the size of the geographic region
- Multivalue Answer - like simple routing but allows you to put health check on each record set