What is AWS Route 53?

What is AWS Route 53?

Every time someone types a URL into their browser, something has to translate that human-readable domain name into an IP address that computers can route to. That translation is DNS — the Domain Name System. AWS Route 53 is Amazon's DNS service, and it does quite a bit more than simple name resolution.

The name comes from the fact that DNS operates on port 53. It's one of those naming choices that makes perfect sense once you know, and means nothing until you do.

Route 53 gives you three main capabilities: domain registration, DNS routing, and health checking. You can buy a domain, point it at your infrastructure, and monitor the health of your endpoints — all from one service.

DNS Basics

Before diving into Route 53 specifics, it helps to understand what DNS actually does.

When you type example.com into your browser, your computer doesn't know where that is. It asks a DNS resolver, which queries a chain of name servers until it finds the authoritative answer — the IP address associated with that domain. That entire lookup typically takes milliseconds, and your browser caches the result so it doesn't have to ask again for a while.

The authoritative name servers are the final source of truth. When you use Route 53, Amazon's name servers become the authoritative servers for your domain. You control what answers they give.

Hosted Zones

In Route 53, a hosted zone is a container for DNS records that belong to a single domain. When you create a hosted zone for example.com, Route 53 assigns four name servers to it. You then point your domain registrar to those name servers, and Route 53 handles all the DNS queries from that point forward.

There are two types:

• Public hosted zones — serve DNS queries from the internet. This is what you use for any domain that needs to be publicly accessible.
• Private hosted zones — serve DNS queries from within your VPC. Useful for internal service discovery where you want api.internal to resolve to a private IP that's only reachable inside your network.

Record Types

DNS records are the entries within your hosted zone that tell Route 53 how to respond to queries. The ones you'll use most often:

A Record — maps a domain name to an IPv4 address. example.com → 192.0.2.1

AAAA Record — same as A, but for IPv6 addresses.

CNAME Record — maps a domain name to another domain name. www.example.com → example.com. One important limitation: you cannot create a CNAME at the zone apex (the root domain itself).

Alias Record — this is Route 53-specific and solves the CNAME limitation. An alias record can point your root domain to AWS resources like CloudFront distributions, S3 website endpoints, Elastic Load Balancers, and other Route 53 records. It's free for queries against AWS resources and resolves faster than CNAMEs.

MX Record — directs email to mail servers. Essential if you're using a custom domain for email.

TXT Record — holds arbitrary text. Commonly used for domain verification (proving you own a domain to services like Google or AWS Certificate Manager) and email authentication (SPF, DKIM).

Routing Policies

This is where Route 53 goes beyond basic DNS. Instead of always returning the same answer for a query, you can apply routing policies that make intelligent decisions:

Simple routing — one record, one answer. The default. Good enough for most straightforward setups.

Weighted routing — distribute traffic across multiple resources by percentage. Send 80% to one server and 20% to another. Useful for gradual rollouts and A/B testing.

Latency-based routing — route users to the region that provides the lowest latency. If you have EC2 instances in both us-east-1 and eu-west-1, users in Europe get routed to the European instance automatically.

Failover routing — route traffic to a primary resource, and automatically switch to a standby if the primary fails a health check. This is how you build DNS-level disaster recovery.

Geolocation routing — route based on the geographic location of the user. Different from latency-based — this is about serving different content to different regions, not just optimizing speed.

Health Checks

Route 53 can monitor the health of your endpoints and react when something goes down. You configure a health check to ping an IP address, domain, or even another health check at regular intervals. If an endpoint fails, Route 53 stops routing traffic to it.

This pairs well with failover routing. Set up a primary instance with a health check, configure a secondary instance as the failover target, and Route 53 handles the switchover automatically when your primary goes down.

Where Route 53 Fits

Route 53 is the front door to your infrastructure. Whether you're hosting a static site on S3, running EC2 instances, or operating across multiple regions, Route 53 is what maps your domain to those resources.

For most projects, you'll pair Route 53 with an AWS essentials setup — a domain, a hosted zone, a few records pointing at your load balancer or S3 bucket, and you're live.

In a future post, I'll cover setting up Route 53 with CloudFront and ACM to serve a static site over HTTPS with a custom domain — end to end. If you're looking to get a production site running on AWS, that's a natural next step from here.

Questions about DNS or Route 53 configuration? Leave a comment or reach out.

-- Nat