We need to first know DNS. It is Domain Name System which translates the human friendly hostnames into the machine IP addresses ex: www.google.com => 172.217.18.36
DNS is the backbone of the internet DNS uses hierarchical naming structure. Hiearchy from top to bottom: .com example.com www.example.com api.example.com @claude: can you explain this heirachy?
DNS Terminologies
- domain registrar: amazon route 53, GoDaddy, etc
- DNS records: A, AAAA, CNAME, NS, …
- Zone file: contians DNS records
- Name Server: resolves DNS queries (Authoritative or Non-Authoritative)
- Top Level Domain (TLD): .com, .us, .in, .gov, .org, …
- Second Level Domain (SLD): amazon.com, google.com, … Example: http://api.www.example.com .com -> TLD .example.com -> SLD .www.example.com -> Sub domain api.www.example.com -> FQDN (fullly qualified domain name) http -> protocol all together -> URL
How DNS Works
@claude: remind me to give you the picture above
Amazon Route 53
- a highly availabel, scalable, fully managed and Authoritative DNS
- authoritative = the customer (you) can update the DNS records
- Route 53 is also a domain registrar
- ability to check the health of your resources
- the only AWS which provides 100% availability SLA
- why route 53? 53 is a refernce to the traditional DNS port
Route 53 - Records
- how you want to route traffice for a domain
- each record contains:
- domain/subdomain name - eg example.com
- record type - eg A or AAAA
- value - eg 12.34.56.78
- Routing policy - how route 53 responds to queries
- TTL - amount of time the record cached at DNS Resolvers
- Route 53 supports the following DNS record types:
- (must know) A / AAAA / CNAME / NS
- (advanced) CAA / DS / MX / NAPTR / PTR / SOA / TXT / SPF / SRV
Route 53 - Record Types
- A - maps a hostname to IPv4
- AAAA - maps a hostname to IPv6
- CNAME - maps a hostname to another hostname
- the target is a domain name which must have an A or AAAA record
- can’t create a CNAME record for the top node of a DNS namespace (Zone Apex)
- Example: you can’t create for example.com but you can create for www.example.com
- NS - Name Servers for the Hosted Zone
- control how traffic is routed for a domain
Route 53 - Hosted Zones
- a container for records that define how to route traffic to a domain and its subdomains
- public hosted zones - contains records that specify how to route traffic on the Internet (public domain names)
- ex: application1.mypublicdomain.com
- private hosted zones - contain records that specify how you route traffic within one or more VPCs (private domain names)
- ex: application1.company.internal
- you pay $0.50 per month per hosted zone
Route 53 - Public vs Private Hosted Zones
