Route 53: DNS Management

Every time someone types your domain name into a browser, a DNS query translates it into an IP address. Amazon Route 53 is AWS's highly available DNS service that not only resolves domain names but also routes traffic based on health checks, geography, and load. In this lesson, we'll explore how to manage DNS with Route 53.

What You'll Learn

By the end of this lesson, you'll understand how DNS works, how to register domains, create hosted zones, configure different record types, and use Route 53's traffic routing policies.

What is DNS?

The Domain Name System (DNS) translates human-readable domain names (like www.example.com) into IP addresses (like 192.0.2.1) that computers use to connect.

How DNS Resolution Works

1. User types: www.example.com
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2. Browser asks: DNS Resolver (usually your ISP)
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3. Resolver queries: Root nameserver (.)
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4. Root refers to: TLD nameserver (.com)
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5. TLD refers to: Authoritative nameserver (example.com)
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6. Authoritative returns: 192.0.2.1
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7. Browser connects to: 192.0.2.1

DNS Records

Different record types serve different purposes:

Record Type	Purpose	Example
A	Maps domain to IPv4 address	example.com → 192.0.2.1
AAAA	Maps domain to IPv6 address	example.com → 2001:0db8::1
CNAME	Alias to another domain	www.example.com → example.com
MX	Mail server for domain	example.com → mail.example.com
TXT	Text data (verification, SPF)	example.com → "v=spf1 include:..."
NS	Nameservers for domain	example.com → ns1.awsdns.com
SOA	Start of authority	Administrative info

What is Route 53?

Route 53 is AWS's DNS web service with three main functions:

1. Domain registration - Buy and manage domain names
2. DNS routing - Translate domains to IP addresses
3. Health checking - Monitor resource availability

Why "Route 53"?

The name refers to TCP/UDP port 53, the standard port for DNS traffic.

Route 53 Features

• 100% availability SLA - One of the few AWS services with this
• Global network - DNS servers on all continents
• Integration - Works seamlessly with other AWS services
• Traffic routing - Multiple routing policies for different needs
• Health checks - Automatic failover on failures

Registering a Domain

You can register domains directly through Route 53.

Step 1: Search for Domain

1. Go to Route 53 console
2. Click "Registered domains" → "Register domain"
3. Enter desired domain name
4. Check availability and pricing

Step 2: Configure Registration

1. Select registration period (1-10 years)
2. Enable/disable auto-renewal
3. Enter contact information
4. Review and purchase

Pricing

Domain pricing varies by TLD:

• .com: ~$13/year
• .org: ~$12/year
• .io: ~$39/year
• .dev: ~$14/year

Domain registration through Route 53 automatically creates a hosted zone.

Hosted Zones

A hosted zone is a container for DNS records for a domain.

Public Hosted Zone

For internet-facing domains. Records are accessible publicly.

Private Hosted Zone

For internal DNS within a VPC. Records only resolve from within associated VPCs.

Creating a Hosted Zone

If you registered your domain elsewhere:

1. Go to Route 53 → "Hosted zones"
2. Click "Create hosted zone"
3. Enter domain name
4. Choose type (public or private)
5. Create

Updating Nameservers

After creating a hosted zone, Route 53 provides 4 nameservers. If your domain is registered elsewhere, update the nameservers at your registrar:

ns-123.awsdns-12.com
ns-456.awsdns-34.net
ns-789.awsdns-56.org
ns-012.awsdns-78.co.uk

Creating DNS Records

Basic A Record

Map your domain to an IP address:

1. Go to hosted zone
2. Click "Create record"
3. Record name: Leave blank for root (example.com) or enter subdomain (www)
4. Record type: A
5. Value: Your server's IP address
6. TTL: 300 (5 minutes for testing, longer for production)

Alias Records

Route 53's special feature for routing to AWS resources without needing their IP:

example.com → d123456.cloudfront.net (Alias)

Alias-compatible targets:

• CloudFront distributions
• Elastic Load Balancers
• S3 buckets (configured for website hosting)
• API Gateway
• Another Route 53 record

Benefits:

• No charge for alias queries (unlike CNAME)
• Works at zone apex (root domain)
• Automatically updates if target IP changes

Common Record Examples

Website:

example.com       A     → 192.0.2.1
www.example.com   CNAME → example.com

With CloudFront:

example.com       A     → Alias to CloudFront distribution
www.example.com   A     → Alias to CloudFront distribution

Email:

example.com       MX    → 10 mail.example.com
mail.example.com  A     → 192.0.2.100
example.com       TXT   → "v=spf1 include:_spf.google.com ~all"

Routing Policies

Route 53 offers several routing policies for different use cases.

Simple Routing

One record → one or more IP addresses. If multiple values, Route 53 returns all (client chooses randomly).

Use case: Single resource, no special routing needed.

Weighted Routing

Distribute traffic by percentage:

Record A: 192.0.2.1  Weight: 70  (70% of traffic)
Record B: 192.0.2.2  Weight: 30  (30% of traffic)

Use case: Gradual deployments, A/B testing, load distribution.

Latency-Based Routing

Route to the region with lowest latency for the user:

Record US: us-east-1 resources
Record EU: eu-west-1 resources
Record Asia: ap-northeast-1 resources

Route 53 measures latency and routes users to the fastest region.

Use case: Global applications needing best performance.

Failover Routing

Active-passive failover using health checks:

Primary: 192.0.2.1 (healthy → traffic goes here)
Secondary: 192.0.2.2 (standby → used if primary fails)

Use case: Disaster recovery, high availability.

Geolocation Routing

Route based on user's geographic location:

USA users → US servers
European users → EU servers
Default → fallback servers

Use case: Localized content, compliance requirements, regional restrictions.

Geoproximity Routing

Route based on geographic location with bias:

US-East resource with bias +25 → Attracts more traffic
US-West resource with bias -25 → Attracts less traffic

Use case: Fine-tuned geographic routing, shifting traffic between regions.

Multi-Value Answer Routing

Return multiple healthy IP addresses:

Returns up to 8 healthy IPs → Client chooses

Use case: Simple load balancing with health checks.

Health Checks

Health checks monitor your resources and enable automatic failover.

Creating a Health Check

1. Go to Route 53 → "Health checks"
2. Click "Create health check"
3. Configure:
   • What to monitor: Endpoint, other health checks, or CloudWatch alarm
   • Endpoint: IP or domain name
   • Protocol: HTTP, HTTPS, or TCP
   • Path: /health (for HTTP/HTTPS)
   • Interval: 30 or 10 seconds
   • Failure threshold: How many failures before unhealthy

Health Check Options

Option	Description
Request interval	30 seconds (standard) or 10 seconds (fast)
Failure threshold	1-10 consecutive failures
String matching	Check response body for expected text
Latency graphs	Monitor response times
Invert status	Healthy when check fails (maintenance mode)

Using Health Checks

Associate health checks with DNS records:

1. Edit record set
2. Set routing policy (failover, weighted, etc.)
3. Associate health check
4. Route 53 only returns healthy records

Private DNS

Use Route 53 for internal DNS within VPCs.

Creating Private Hosted Zone

1. Create hosted zone
2. Choose "Private hosted zone"
3. Associate with VPC(s)

Use Cases

• Internal service discovery (api.internal)
• Split-horizon DNS (different internal vs external IPs)
• Custom domain names for internal resources

Hybrid DNS

Connect on-premises DNS with Route 53:

• Outbound endpoints: Resolve Route 53 records from on-premises
• Inbound endpoints: Resolve on-premises records from VPCs

Domain Transfer

Move an existing domain to Route 53:

Steps

1. Unlock domain at current registrar
2. Get authorization code from current registrar
3. In Route 53: Domains → Transfer domain
4. Enter domain and authorization code
5. Pay transfer fee
6. Confirm transfer via email

Transfers typically complete in 5-7 days.

Best Practices

TTL Settings

Use Case	Recommended TTL
Testing/migration	60-300 seconds
Production, stable	3600-86400 seconds
Failover records	60 seconds

Lower TTL = faster propagation but more DNS queries.

Security

• Enable DNSSEC for domain (prevents DNS spoofing)
• Use IAM to restrict who can modify records
• Monitor with CloudWatch and CloudTrail

Reliability

• Use health checks for critical records
• Have failover records for high availability
• Test failover scenarios regularly

Route 53 Pricing

Feature	Cost
Hosted zone	$0.50/month
Standard queries	$0.40/million
Latency-based queries	$0.60/million
Geo queries	$0.70/million
Health checks	$0.50/month (endpoint)
Domain registration	Varies by TLD

Free Tier

• Alias queries to AWS resources (CloudFront, ELB, S3) are free
• No free tier for hosted zones or health checks

Key Takeaways

• Route 53 provides domain registration, DNS hosting, and health checking
• Hosted zones contain DNS records for your domain
• Alias records route to AWS resources without needing IP addresses
• Routing policies enable weighted, latency-based, failover, and geo routing
• Health checks monitor endpoints and enable automatic failover
• Private hosted zones provide internal DNS within VPCs
• 100% availability SLA makes Route 53 highly reliable

What's Next

You now understand how to route users to your applications. But how do you keep those applications secure? In the next lesson, we'll explore AWS security best practices, from IAM to encryption and beyond.