Amazon Route 53: DNS and Routing
Learn how Amazon Route 53 translates domain names to IP addresses, registers domains, and routes traffic with health-aware policies.
Learning outcomes
By the end of this lesson, you will be able to:
- Explain what DNS does and why it matters.
- Describe Amazon Route 53 as a DNS service and domain registrar.
- Distinguish between public and private hosted zones.
- Identify the four routing policies tested on the CCP exam.
- Explain how Route 53 health checks enable automatic failover.
What is DNS?
The Domain Name System (DNS) is the phone book of the internet. When you type www.example.com into a browser, DNS translates that human-readable name into an IP address (like 93.184.216.34) so your computer knows where to send the request.
Without DNS, you'd need to memorize IP addresses for every website you visit.
What is Amazon Route 53?
Amazon Route 53 is AWS's highly available, scalable DNS web service. It does three things:
- DNS resolution — Translates domain names to IP addresses (or other endpoints like CloudFront distributions and load balancers).
- Domain registration — You can buy and manage domain names directly through Route 53.
- Health checking — Route 53 monitors the health of your endpoints and can route traffic away from unhealthy ones.
Note
The name "Route 53" refers to port 53, the standard port used for DNS traffic.
Hosted zones
A hosted zone is a container for DNS records for a domain. Route 53 supports two types:
Public hosted zone
Routes traffic on the public internet. When someone types your domain into a browser, the public hosted zone tells them where to go.
Example: example.com → your ALB's public IP.
Private hosted zone
Routes traffic within one or more VPCs. Internal services can use friendly names instead of IP addresses — but those names are not resolvable from the public internet.
Example: api.internal.example.com → a private ALB inside your VPC.
Routing policies
Route 53 offers several routing policies. For the CCP exam, know these four at a high level:
| Policy | What it does | When to use it |
|---|---|---|
| Simple | Routes to a single resource | One web server, one endpoint |
| Weighted | Splits traffic by percentage (e.g., 80/20) | A/B testing, gradual migrations |
| Failover | Routes to a standby if the primary is unhealthy | Active-passive disaster recovery |
| Latency-based | Routes to the Region with lowest latency for the user | Multi-Region applications |
Tip
Exam pattern: If a question describes routing traffic to a backup when the primary fails, the answer is failover routing with health checks.
Health checks
Route 53 can monitor the health of your endpoints by periodically sending requests to them. If an endpoint stops responding (or returns errors), Route 53 marks it unhealthy and stops routing traffic to it.
Health checks work with failover routing to create automatic disaster recovery:
- Route 53 checks the primary endpoint every 10 or 30 seconds.
- If the primary fails, Route 53 automatically redirects DNS responses to the secondary (standby) endpoint.
- When the primary recovers, traffic shifts back.
This happens at the DNS level — no load balancer or application change required.
Route 53 vs CloudFront
These two services are often confused. They complement each other but serve different purposes:
| Route 53 | CloudFront | |
|---|---|---|
| Primary role | DNS — resolves names to endpoints | CDN — caches and delivers content from edge locations |
| Operates on | Domain names and IP resolution | Content delivery and caching |
| Common pattern | Routes users to a CloudFront distribution | Serves cached content from the nearest edge location |
A typical setup: Route 53 resolves www.example.com → a CloudFront distribution → which pulls content from an S3 bucket or ALB origin.
Micro-activity: Match the Routing Policy
Match each routing policy to its use case
Examples
Choose one, then match it on the right
Characteristics
Select an example first
0 of 4 matched so far.
Summary
- DNS translates domain names to IP addresses.
- Route 53 is AWS's managed DNS service, domain registrar, and health checker.
- Hosted zones can be public (internet) or private (VPC-internal).
- Routing policies: simple, weighted, failover, latency-based.
- Health checks enable automatic failover to a standby endpoint.
Knowledge Check
Next lesson
Lesson 4: Amazon CloudFront — Content Delivery