Route53 Guide for the AWS Certified Solutions Architect Associate Exam

Amazon Route 53 is a scalable and highly available Domain Name System (DNS) web service released by Amazon Web Services (AWS) in December 2010. Route 53 effectively connects user requests to infrastructure running in AWS, such as Amazon EC2 instances, Elastic Load Balancing load balancers, or Amazon S3 buckets, and can also be used to route users to infrastructure outside of AWS.

Fun fact
It was named humorously after the U.S. Route 66 to signify its critical role in navigating the internet and after the fact that DNS is on port 53

What is a DNS Web Service?

A DNS web service is an internet service that translates human-friendly domain names (like www.example.com) into machine-readable IP addresses (like 192.0.2.1), facilitating the routing of traffic over the internet. This translation is vital because while domain names are easy for people to remember, computers and machines access websites based on IP addresses.

Key Terms and Definitions in Route 53

Hosted Zones - A hosted zone is a container that holds information about how you want to route traffic for a domain (and its subdomains).

Resource Record Sets - These are the fundamental elements of a hosted zone, containing information about how to respond to DNS queries. A record set includes the domain or subdomain name, the record type, and the data it responds with.

TTL (Time to Live) - This setting determines how long a DNS resolver is supposed to cache the DNS query before requesting a new one. Lower TTL can help manage changes in DNS information more quickly.

Alias - An alias record in AWS Route 53 allows DNS queries to route directly to AWS resources like ELB, CloudFront, or S3, automatically adapting to IP changes without DNS query charges.

Common Record Types in Route 53

Route 53 supports multiple types of records, which define the method of resolution:

• A Records: Address records that map domain names to IPv4 addresses.
• AAAA Records: Map domain names to IPv6 addresses.
• CNAME Records: Canonical Name records alias one domain name to another.
• MX Records: Mail Exchange records route emails to correct email servers.
• PTR Records: Pointer records map a network interface (IP) to a hostname.

Hosted Zones

• Public Hosted Zones - Manage how the public accesses your traffic by associating your domain name with your AWS resources.
• Private Hosted Zones - Manage the DNS records for your internal network resources, and are not resolvable over the public internet.

Routing Policies

Routing policies in Route 53 help control how DNS responds to queries and can be used to configure failover, load balancing, and latency optimizations:

• Simple Routing Policy: This policy routes DNS queries to a single specific resource, such as a web server hosting your domain’s content.
• Failover Routing Policy: It directs traffic to a primary resource under normal conditions and switches to a secondary, backup resource if the primary fails.
• Geolocation Routing Policy: This policy routes traffic based on the geographical location of the user, helping deliver localized content and reduce latency.
• Geoproximity Routing Policy: Routes traffic by assessing the physical distance between your resources and your users, with options to adjust traffic flow between different locations.
• Latency Routing Policy: This policy helps route traffic to the AWS region that offers the best latency to the user, improving speed and performance.
• IP-based Routing Policy: Routes traffic specifically based on the IP address origin of the user’s request, allowing for precise regional routing.
• Multivalue Answer Routing Policy: Provides multiple resource answers to DNS queries, choosing up to eight healthy options at random to improve availability.
• Weighted Routing Policy: Allows you to assign different weights to various resources, controlling how much traffic each receives based on their assigned weight.

Health checks

In Amazon Route 53, health checks are crucial for monitoring the health of your resources and ensuring that traffic is only routed to healthy endpoints. Health checks automatically send requests at regular intervals to an endpoint specified by you to verify its responsiveness and availability. If a resource fails to respond as expected, Route 53 can reroute traffic to other healthy endpoints based on your DNS configurations. This feature is particularly useful in failover routing scenarios, enabling dynamic response to outages and maintaining service availability without manual intervention.

Sample questions

Here are some sample AWS Certified Solutions Architect Associate exam questions, focusing on AWS Route 53 and related AWS services:

Question 1: A company is using Route 53 for DNS services. They need to route traffic to different regions based on the geographic location of their users to reduce latency. Which Route 53 routing policy should be used?

A. Simple Routing

B. Geolocation Routing

C. Latency Routing

D. Multivalue Answer Routing

Correct Answer: B. Geolocation Routing. It allows traffic routing based on the geographic location of the user, which can help reduce latency by directing users to the nearest regional resources.

Question 2: An organization wants to configure their web application to handle failovers between two Amazon EC2 instances in different availability zones using Route 53. Which routing policy should they implement?

A. Weighted Routing

B. Geoproximity Routing

C. Failover Routing

D. Simple Routing

Correct Answer: C. Failover Routing. It is designed for active-passive failover setups, ensuring that if the primary resource becomes unavailable, traffic automatically reroutes to a secondary, standby resource.

Question 3: If a company wants to manage DNS records and route users to an Amazon CloudFront distribution with Route 53, which type of Route 53 record set should they use?

A. A Alias

B. CNAME

C. MX

D. TXT

Correct Answer: A. A Alias. Can route DNS queries directly to certain AWS resources like an Amazon CloudFront distribution without causing additional DNS query charges, making it a suitable choice for AWS integrations.

Question 4: To improve DNS query efficiency and manage peak loads, a company uses Route 53. Which Route 53 feature allows them to return multiple health-checked resources for each DNS query?

A. Simple Routing

B. Geolocation Routing

C. Multivalue Answer Routing

D. Latency Routing

Correct Answer: C. Multivalue Answer Routing. This feature enables Route 53 to respond to DNS queries with up to eight healthy resources, chosen at random, which helps in managing high traffic loads and ensuring high availability.

Question 5: A company needs to distribute incoming network traffic across multiple Amazon EC2 instances automatically based on the current load of each instance. Which Route 53 routing policy should be used?

A. Weighted Routing

B. Latency Routing

C. Geoproximity Routing

D. IP-based Routing

Correct Answer: A. Weighted Routing. Allows traffic distribution across multiple resources by assigning different weights, enabling traffic management based on the current load of each resource.

Question 6: If a company wants Route 53 to route traffic based on the geographic distance between their users and their resources, which routing policy should they implement?

A. Geolocation Routing

B. IP-based Routing

C. Geoproximity Routing

D. Latency Routing

Correct Answer: C. Geoproximity Routing

Question 7: How does Route 53 handle DNS queries to ensure availability and load balancing when configured with Multivalue Answer Routing?

A. By returning all healthy resources associated with a DNS query

B. By rotating DNS responses based on weight

C. By providing a single resource based on proximity

D. By redirecting to a secondary resource when the primary fails

Correct Answer: A. By returning all healthy resources associated with a DNS query. This improves reliability during peak load times.

Question 8: Which type of record set in Route 53 can be used to route traffic to an AWS resource without incurring standard DNS resolution charges?

A. CNAME

B. MX

C. Alias

D. TXT

Correct Answer: C. Alias. Used to route traffic directly to specific AWS resources such as ELB, CloudFront, or S3 without incurring standard DNS resolution charges.

Question 9: What is the main benefit of using an Alias record over a CNAME record in Route 53?

A. Alias records can point to any website URL

B. Alias records are cheaper because they do not incur DNS query charges

C. Alias records can only be used within AWS

D. Alias records provide better security

Correct Answer: B. Alias records are cheaper because they do not incur DNS query charges

Question 10: When configuring Route 53 with Failover Routing, what determines when traffic is routed to the failover site?

A. The primary site's geographic location

B. Manual switching by an administrator

C. Automated health checks determining the primary site’s availability

D. Traffic volume exceeding a predetermined threshold

Correct Answer: C. Automated health checks determining the primary site’s availability. That ensures continuity of service.

Question 11: Why is it important to configure an appropriate TTL (Time to Live) for DNS records in Route 53?

A. To ensure DNS records are updated across all DNS servers simultaneously

B. To control how long DNS resolvers cache the DNS records before querying Route 53 again

C. To increase the security of DNS records against spoofing

D. To directly reduce the cost of DNS management

Correct Answer: B. To control how long DNS resolvers cache the DNS records before querying Route 53 again. Setting the correct TTL for DNS records is crucial since it can affect how quickly changes to DNS records propagate throughout the internet and impact the load on DNS servers.

Question 12: What is the primary purpose of a hosted zone in Amazon Route 53?

A. To link to external DNS services

B. To manage the DNS records for a specific domain

C. To configure SSL/TLS certificates for domain security

D. To monitor the traffic coming to your domain

Correct Answer: B. To manage the DNS records for a specific domain. A hosted zone in Amazon Route 53 serves as a container for all DNS records for a specific domain, providing an organized way to manage and configure how traffic is routed for that domain.