🌍 Amazon Route 53 Overview

Amazon Route 53 is a Managed DNS (Domain Name System) service.

• DNS = "Phonebook of the Internet"
• It helps clients resolve domain names (URLs) to IP addresses.
• Route 53 supports multiple record types to map names to resources.

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📘 Common DNS Record Types

Record Type	Description	Example
A Record	Maps domain → IPv4 address	www.example.com → 12.34.56.78
AAAA Record	Maps domain → IPv6 address	www.example.com → 2001:db8::7334
CNAME Record	Maps hostname → another hostname	search.example.com → www.example.com
Alias Record	Maps domain → AWS resource (ELB, CloudFront, S3, RDS, etc.)	example.com → AWS Resource

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🚦 How Route 53 Works (High-Level)

1. User enters myapp.mydomain.com in the browser.
2. Browser sends a DNS query to Route 53.
3. Route 53 returns the IP address for that domain.
4. Browser connects to that IP → reaches the correct server → gets HTTP response.

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⚙️ Route 53 Routing Policies

Used to determine how traffic is directed based on use case.

Routing Policy	Health Check	Description	Use Case
Simple	❌ No	Returns a single resource for a domain	Single web server
Weighted	✅ Yes	Distributes traffic across multiple resources based on assigned weights	Load balancing (e.g., 70%-20%-10%)
Latency-Based	✅ Yes	Routes users to the region with the lowest network latency	Global apps — minimize latency
Failover	✅ Yes	Routes traffic to a standby resource when the primary fails	Disaster recovery (active-passive setup)

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🧩 Key Exam Tips

• Route 53 = Managed DNS
• Simple = 1 target, no health checks
• Weighted = distribute load
• Latency = choose nearest region
• Failover = DR / backup routing
• Alias records integrate with AWS resources (ELB, CloudFront, etc.)

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🌐 Route 53 + EC2 — Latency-Based Routing

This guide shows how to host simple web servers in two AWS regions and route users automatically to the lowest-latency region using Amazon Route 53.

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1. Register a Domain (Route 53)

1. AWS Console → Route 53 → Create hosted zones
2. Select Public hosted zone
3. Click Create hosted zone
4. This zone will store DNS records

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2. Launch EC2 Instances (Two Regions)

• Security Group: allow HTTP (port 80) inbound
• Launch, then copy each instance’s Public IPv4 Address
• Ireland(54.155.150.72)
• Oregon(34.214.42.89)

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3. Create Latency-Based Records (Route 53)

1. Hosted Zone → Create record
2. Record name: www Type: A Routing policy: Latency
3. Add first record:
   • Value: Ireland EC2 IP
   • Region: EU (Ireland) Identifier: “Ireland-Instance”
4. Add second record:
   • Value: US EC2 IP
   • Region: US West (Oregon) Identifier: “US-Instance”

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4. Test Routing

Method	Command / Action
Browser	Open http://www.himanshupapola.tech
DNS	nslookup www.himanshupapola.tech
Cross-region test	Use a VPN to switch regions and reload the site

Expected:

• From Europe → “Hello from Ireland”
• From US → “Hello from US”

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5. Cleanup

Task	Command / Action
Terminate EC2	aws ec2 terminate-instances --instance-ids <IDs>
Delete DNS records	Remove A records for www
Delete hosted zone	aws route53 delete-hosted-zone --id <ZONEID>
Disable auto-renew	aws route53domains disable-domain-auto-renew --domain-name mydomain.com

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💰 Cost & Notes

Resource	Typical Cost
Domain	~$12/yr (not fixed)
Hosted Zone	~$0.50/month
EC2 (t2.micro)	Free tier eligible or per-hour cost
Data Transfer	Regional rates apply

Tip: Use short TTL (e.g., 60 seconds) for faster DNS propagation while testing.