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Difficulty: MediumAmazon Route 53 DNS Configuration and Routing Policies

A SysOps Administrator is configuring Amazon Route 53 for a company's new corporate landing page. The landing page is hosted on an Amazon S3 bucket configured for static website hosting. The company wants the landing page to be accessible directly via the apex domain (example.com). Which configuration should the administrator use to map the apex domain to the Amazon S3 website endpoint?

  1. A
    Create a CNAME record for the apex domain (example.com) that points to the S3 bucket website endpoint domain name.
  2. Create an Alias A record for the apex domain (example.com) that points to the S3 bucket website endpoint.Answer
  3. C
    Create an Alias A record for the apex domain (example.com) with a Failover routing policy pointing to the S3 bucket website endpoint, but do not associate any Route 53 health checks.
  4. D
    Create a CNAME record for the apex domain (example.com) and configure a Geolocation routing policy pointing to the S3 bucket website endpoint.

Answer

Create an Alias A record for the apex domain (example.com) that points to the S3 bucket website endpoint.
The correct configuration is to create an Alias A record for the apex domain pointing to the S3 bucket website endpoint. Route 53 Alias records are a proprietary extension that allows mapping apex domains directly to specific AWS resources, such as S3 buckets, CloudFront distributions, and ELBs. Unlike standard CNAME records, Alias records resolve to A records during DNS queries, satisfying the requirement that the zone apex must have an A record (or similar address records) and avoiding conflicts with mandatory zone-level records like SOA and NS.

Step-by-Step Solution

1
Analyze the requirements for routing traffic for the apex domain (example.com) to a static website hosted on Amazon S3.
The target domain is the zone apex, and the destination is an Amazon S3 website endpoint.
Routing rules at the zone apex level have specific DNS specification constraints that dictate which record types are permitted.
2
Determine the viability of CNAME records at the zone apex.
According to DNS standards (RFC 1034), CNAME records cannot coexist with other records (such as SOA and NS) that must exist at the zone apex.
Using a CNAME record at the zone apex would break DNS resolution for mandatory root-level records.
3
Select the correct AWS Route 53 specific feature that bypasses the zone apex limitation.
Create an Alias record pointing directly to the S3 website endpoint.
Route 53 Alias records act like a CNAME but are resolved internally to IP addresses and presented as A records, allowing them to safely exist at the zone apex.

Key Concept

Route 53 Alias records resolve zone apex limitations by mapping directly to AWS resources.
Estimated Time:1m 30s
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Topics

Amazon Route 53 DNS Configuration and Routing Policies

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