Route53

Amazon Route53

Route53 is a DNS (Domain Name System) service provided by AWS.

DNS is used for domain resolution (conversion of domain names to IP addresses)

It is also a domain registrar (where we can register our websites), and it allows us to create and manage DNS records (A, AAAA, MX, CNAMEs, and more). It also supports different routing strategies (policies) and health checks on resources.

DNS is hierarchical; the DNS hierarchy (domain name space) helps in resolving Domains.

DNS Resolution at High Level

DNS resolution starts on the client-side DNS resolver (local DNS resolver); it checks whether the IP address is available for the requested domain in its local cache; if it is and has not expired (under TTL-Time To Live), then it is returned, and there is no initiation of a new DNS resolution process.

Name Servers are also known as DNS Servers.

If it is not present or not under TTL, then the DNS resolver contacts the recursive DNS servers (Local DNS Servers) to handle resolution on its behalf. Recursive DNS servers have their own local cache, which checks whether it has the record in it. If it is, then it returns; otherwise, the DNS resolution process continues, which is called the recursive resolution process.

Recursive DNS servers query the Root Name Servers to find out Authoritative Name Servers for TLDs like.com,.org,.uk, etc.

There are 13 Root name servers around the world that provide information about TLDs.

Authoritative Name Servers for TLD refers to TLD DNS Servers

Recursive DNS server, then queries Authoritative Name Servers for TLDs for Authoritative Name Servers responsible for specific domains, like example.com, google.com, etc.

Recursive DNS servers then query Authoritative Name Servers for specific Domains, which return the actual DNS records, which contain IP addresses.

After resolution at the TLD, there can be resolution at the SLD with the help of Authoritative Name Servers.

Authoritative Name Servers for SLD refers to SLD DNS Servers.

Here is the overall explanation of the DNS resolution in picture representation.

DNS Resolution at Low Level

Route 53 has Hosted zones, which are containers of records. They are Authoritative Name Servers and are associated with domains or subdomains.

There are different routing policies supported by Route 53 they are simple, weighted, failover, latency-based, geolocation, multi-value answer, and geoproximity.

It also supports Health Checks and Automatic DNS failover (traffic is routed to a different resource when one of the resources goes down).