Amazon Route 53 hosted zones are fundamental containers that hold information about how you want to route traffic for a specific domain and its subdomains. As an AWS SysOps Administrator, understanding hosted zones is essential for managing DNS infrastructure effectively.
There are two types of ho…Amazon Route 53 hosted zones are fundamental containers that hold information about how you want to route traffic for a specific domain and its subdomains. As an AWS SysOps Administrator, understanding hosted zones is essential for managing DNS infrastructure effectively.
There are two types of hosted zones:
**Public Hosted Zones** contain records that specify how to route traffic on the internet. When you register a domain or transfer DNS management to Route 53, a public hosted zone is created automatically. This zone responds to DNS queries from anywhere on the internet, making your resources publicly accessible.
**Private Hosted Zones** contain records that determine how traffic is routed within one or more Amazon VPCs. These zones enable you to use custom domain names for internal resources that should not be accessible from the public internet. You must associate a VPC with the private hosted zone for DNS resolution to work.
**Key Components:**
- **Name Servers (NS)**: Each hosted zone receives four authoritative name servers that Route 53 assigns
- **Start of Authority (SOA)**: Contains administrative information about the zone
- **DNS Records**: A, AAAA, CNAME, MX, TXT, and other record types that define routing behavior
**Important Considerations:**
- You are charged $0.50 per hosted zone per month for the first 25 hosted zones
- Hosted zones can contain up to 10,000 records by default
- When creating a private hosted zone, you must enable DNS hostnames and DNS resolution in your VPC settings
- You can associate multiple VPCs with a single private hosted zone, even across different AWS accounts
**Best Practices:**
- Use alias records when pointing to AWS resources to avoid additional charges
- Implement health checks for failover routing policies
- Consider using separate hosted zones for production and development environments
Route 53 Hosted Zones - Complete Guide for AWS SysOps Administrator Associate
What are Route 53 Hosted Zones?
A hosted zone is a container for DNS records that define how traffic should be routed for a specific domain and its subdomains. Think of it as a database that holds all the DNS information for your domain.
Types of Hosted Zones:
1. Public Hosted Zones These contain records that specify how to route traffic on the internet. When you register a domain or transfer DNS management to Route 53, a public hosted zone is created. It responds to DNS queries from anywhere on the public internet.
2. Private Hosted Zones These contain records that specify how to route traffic within one or more Amazon VPCs. Private hosted zones allow you to use custom domain names for your internal AWS resources. They are not accessible from the public internet.
Why are Hosted Zones Important?
- They provide the foundation for all DNS management in AWS - Enable routing of traffic to AWS resources like EC2, ELB, S3, and CloudFront - Support complex routing policies including weighted, latency-based, geolocation, and failover routing - Private hosted zones enable internal DNS resolution for hybrid cloud architectures - Essential for high availability and disaster recovery configurations
How Hosted Zones Work:
1. Creation: When you create a hosted zone, Route 53 automatically creates a Name Server (NS) record and a Start of Authority (SOA) record.
2. Name Servers: Each hosted zone is assigned four name servers. For public hosted zones, you must update your domain registrar to use these name servers.
3. Record Sets: You add record sets (A, AAAA, CNAME, MX, TXT, etc.) to define how DNS queries should be answered.
4. DNS Resolution: When a DNS query is made, Route 53 uses the records in your hosted zone to respond with the appropriate IP address or routing information.
Key Features:
- Alias Records: AWS-specific record type that can point to AWS resources like ELB, CloudFront, or S3 buckets at no additional charge for queries - Health Checks: Can be associated with records to enable DNS failover - Traffic Policies: Complex routing configurations can be created and applied to hosted zones - Split-View DNS: Using both public and private hosted zones with the same domain name for different responses based on query origin
Private Hosted Zone Requirements:
- VPC must have enableDnsHostnames and enableDnsSupport set to true - Must associate the private hosted zone with the VPC(s) that need access - Can associate VPCs from different AWS accounts using authorization
Pricing Considerations:
- Charged per hosted zone per month ($0.50 for first 25 zones) - Charged per million queries (varies by routing policy type) - Alias queries to AWS resources are free
Exam Tips: Answering Questions on Route 53 Hosted Zones
1. Public vs Private Hosted Zones: If a question mentions internal resources, VPCs, or private DNS resolution, think private hosted zones. If it mentions internet-facing applications, think public hosted zones.
2. Private Hosted Zone VPC Settings: Remember that both enableDnsHostnames and enableDnsSupport must be enabled on the VPC. This is a common exam topic.
3. Alias Records vs CNAME: Alias records work at the zone apex (root domain), while CNAMEs cannot. Alias records to AWS resources have no query charges.
4. Cross-Account VPC Association: Private hosted zones can be associated with VPCs in other AWS accounts through authorization. Look for scenarios involving multiple accounts sharing DNS.
5. Split-View DNS: When questions describe different responses needed for internal vs external users for the same domain, the answer involves using both public and private hosted zones.
6. Name Server Updates: For domains registered elsewhere, you must update the NS records at the registrar to point to Route 53 name servers.
7. Health Checks and Failover: Health checks can only be associated with records in public hosted zones. Private hosted zones support failover through other mechanisms.
8. Hosted Zone Delegation: NS records can be used to delegate subdomains to different hosted zones. Look for this in questions about managing different environments or teams.
9. Common Troubleshooting: If DNS resolution fails for private hosted zones, check VPC DNS settings and hosted zone associations first.