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Amazon Route 53 is AWS's highly available and scalable Domain Name System (DNS) web service. It performs three main functions: domain registration, DNS routing, and health checking. Route 53 is the entry point for almost every request that reaches your AWS infrastructure — translating human-friendly domain names into IP addresses that computers use.
The Domain Name System translates domain names like www.example.com into IP addresses like 54.200.10.5. Without DNS, users would have to remember numeric addresses for every website.
User types www.example.com
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1. Browser checks local cache
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2. Query goes to recursive resolver (ISP or 8.8.8.8)
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3. Resolver queries root name server → "ask .com TLD"
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4. Resolver queries .com TLD server → "ask ns-xxx.awsdns-xx.com"
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5. Resolver queries Route 53 authoritative name server
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6. Route 53 returns 54.200.10.5
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7. Browser connects to 54.200.10.5
A hosted zone is a container for DNS records for a domain. There are two types:
| Type | Purpose | Example |
|---|---|---|
| Public hosted zone | Route internet traffic for a domain | example.com accessible from anywhere |
| Private hosted zone | Route traffic within a VPC | internal.example.com resolved only inside your VPC |
| Record Type | Purpose | Example |
|---|---|---|
| A | Maps a domain to an IPv4 address | example.com → 54.200.10.5 |
| AAAA | Maps a domain to an IPv6 address | example.com → 2001:db8::1 |
| CNAME | Maps a domain to another domain name | www.example.com → example.com |
| Alias | AWS-specific; maps to AWS resources (free queries) | example.com → ALB DNS name |
| MX | Mail exchange servers | example.com → mail.example.com |
| TXT | Arbitrary text (SPF, DKIM, verification) | example.com → "v=spf1 include:..." |
| NS | Name servers for the hosted zone | Auto-created by Route 53 |
| SOA | Start of authority | Auto-created by Route 53 |
Alias records are unique to Route 53. They work like CNAME but:
example.com — CNAME cannot)Always prefer Alias records when pointing to AWS resources.
Route 53 offers several routing policies that control how DNS queries are answered:
Returns one or more IP addresses. No health checks or intelligence. Good for a single resource.
example.com → 54.200.10.5
Distribute traffic across resources based on weights you assign.
| Record | IP | Weight | Traffic Share |
|---|---|---|---|
| A | 54.200.10.5 | 70 | 70% |
| A | 54.200.10.6 | 30 | 30% |
Use case: canary deployments — send 10% of traffic to a new version.
Route users to the AWS Region that provides the lowest latency for them.
User in London → eu-west-2 ALB
User in New York → us-east-1 ALB
User in Tokyo → ap-northeast-1 ALB
Route traffic to a primary resource and automatically switch to a secondary if the primary fails a health check.
Primary: ALB in eu-west-2 (active)
Secondary: S3 static "maintenance" page
If the ALB health check fails, Route 53 returns the S3 endpoint.
Route traffic based on the geographic location of the user (continent, country, or US state).
| Location | Endpoint |
|---|---|
| Europe | eu-west-2 ALB |
| North America | us-east-1 ALB |
| Default | eu-west-2 ALB |
Use case: compliance (keep European data in Europe) or localised content.
Route traffic based on geographic location with a bias — you can shift more or less traffic to a Region by adjusting the bias value. Requires Route 53 Traffic Flow.
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