aws route53.

So what is Route53, what is the use of it, and why do we use it?

Before we start with Route53, let’s understand what DNS (Domain Name System) is.

We have two types of IP addresses: IPv4 (32 bit field, approx 4 billion different addresses) & IPv6 (128 bits).

If you want to know how DNS name resolution works, see this blog: https://levelup.gitconnected.com/how-does-dns-domain-name-system-query-gets-resolved-137a9e445ad8?source=post_page-----f3657b01ffa2---------------------------------------

Let’s head over to our main topic: Route53.

In AWS, Route53 is a global managed DNS (Domain Name System). DNS is a collection of rules and records which helps clients understand how to reach a server through URLs.

DNS operates on port 53. Amazon decided to call it Route 53—that’s where the name comes from.

Route53 is a global service. You need a domain to work with Route53: go to the Route53 service → Register domain → enter the domain → check availability → add to cart → continue.

Route53 can work with:

• Public domain names you own (or buy) or private domain names that can be resolved by your instances in your VPCs.

• Many features such as load balancing, health checks, and routing policies like Simple, Failover, Geolocation, Latency, Weighted, and Multi value.

• Cost: $0.50 per month per hosted zone.

When you create a hosted zone in Route53, two records are automatically created: SOA and NS.

Hosted Zone (SOA & NS Records)

TTL (Time to Live)

• TTL is mandatory for each DNS record. It is the length that a DNS record is cached on either the resolving server or the user's device.

• Lower TTL means changes to DNS records propagate faster.

• You must define TTL when you create a record set.

TTL (Time to Live)

How Amazon Route 53 Routes Traffic for Your Domain (Source AWS Official)

When you create basic records, you specify the following values:

• Name

• Type

• Alias

• TTL (Time to Live)

• Value

• Routing Policy

Records (common types)

1

SOA (Start of Authority)

SOA stores information about:

• Name of server that supplied the data for the zone.

• The administrator of that zone & current version of the data file.

Example: ns-2048.awsdns-64.net. hostmaster.example.com. 1 7200 900 1209600 86400

Route53 name server that creates the SOA record: ns-2048.awsdns-64.net. Email address of administrator: hostmaster.example.com

2

NS Record (Name Server Record)

NS records are your name server records used by top-level domain servers to direct traffic to the authoritative DNS server that contains the records.

• When you create a hosted zone in Route53, an NS record is automatically created.

3

A Record (Address — URL to IPv4)

• The “A” record maps a domain name to an IPv4 address.

• Example: http://medium.com might point to http://126.78.98.90

4

CNAME (Canonical Name — URL to URL)

• CNAME points a subdomain (non-root domain) to another domain name.

• Use: something.mydomain.com → otherdomain.example.com

• Note: CNAMEs are used only for non-root domains.

5

Alias Record

• Alias records point a URL to an AWS resource (e.g., Elastic Load Balancer, CloudFront distribution, or S3 bucket configured as a website).

• Alias records are Route53-specific and can be used at the zone apex (root domain).

6

AAAA (URL to IPv6)

• AAAA maps a domain name to an IPv6 address (IP version 6).

7

MX Record (Mail Exchanger)

• MX records specify the mail server(s) responsible for accepting email messages on behalf of a domain.

• You can configure multiple MX records for redundancy and load balancing.

Routing policies

When you create a record, you choose a routing policy, which determines how Amazon Route 53 responds to queries.

Routing Policy

There are six routing policies in Route53. Below they are presented as steps.

1

Simple routing

• Maps a domain to a single resource.

• You can have one record with multiple IP addresses; Route53 returns all values in random order.

• Use when you need to redirect to a single resource.

• You can’t attach health checks to simple routing policy. If multiple values are returned, the client chooses one.

2

Weighted routing

• Controls the percentage of requests sent to specific endpoints.

• Useful for testing (e.g., 1% of traffic to a new app version) or splitting traffic across regions.

• You can associate health checks with weighted records.

Weighted Policy

3

Latency routing

• Routes traffic based on the lowest network latency for the end user.

• Redirects to the region with the least latency from the user’s location.

• Latency is evaluated in terms of user-to-designated-AWS-region.

Latency Routing Policy

4

Failover routing

• Routes traffic to a primary resource when healthy, and to a secondary resource when the primary is unhealthy.

• Can be used to route to S3 website endpoints, ELBs, or complex record trees.

• You can associate health checks with failover routing.

5

Geolocation routing

• Routes traffic based on the geographic location of DNS queries' origin.

• Example: route all queries from Europe to an ELB in the Frankfurt region.

• You can associate health checks with geolocation routing.

Geolocation Policy

6

Multi Value routing

• Returns multiple values for a DNS query and routes traffic to multiple IP addresses.

• Use when you want to return multiple answers and associate records with Route53 health checks.

• Up to 8 healthy records are returned for each multi-value query.

• Note: Multi Value routing is not a substitute for an ELB.

This covers the essential Route53 records and routing policies.