Why DNS management matters in AWS - Test Your Understanding

Practice - 5 Tasks

1fill in blank

easy

Complete the code to create a Route 53 hosted zone with the correct domain name.

AWS

resource "aws_route53_zone" "primary" {
  name = "[1]"
}

Drag options to blanks, or click blank then click option'

Avpc-123abc

Bmybucket

Cus-east-1

Dexample.com

Attempts:

3 left

💡 Hint

Common Mistakes

Using a bucket name instead of a domain name.

Using a region or VPC ID instead of a domain name.

The name field must be the domain name you want to manage in Route 53, like example.com.

2fill in blank

medium

Complete the code to create an A record pointing to an IP address in Route 53.

AWS

resource "aws_route53_record" "web" {
  zone_id = aws_route53_zone.primary.zone_id
  name    = "www"
  type    = "A"
  ttl     = 300
  records = ["[1]"]
}

Drag options to blanks, or click blank then click option'

Avpc-123abc

Bexample.com

C192.0.2.44

Dus-east-1

Attempts:

3 left

💡 Hint

Common Mistakes

Using a domain name instead of an IP address for an A record.

Using AWS resource IDs or region names instead of IP addresses.

The records field for an A record must be an IP address, like 192.0.2.44.

3fill in blank

hard

Fix the error in the code by selecting the correct record type for a domain alias to an S3 website endpoint.

AWS

resource "aws_route53_record" "alias" {
  zone_id = aws_route53_zone.primary.zone_id
  name    = "static"
  type    = "[1]"
  alias {
    name                   = aws_s3_bucket.website.website_endpoint
    zone_id                = aws_s3_bucket.website.hosted_zone_id
    evaluate_target_health = false
  }
}

Drag options to blanks, or click blank then click option'

AA

BCNAME

CTXT

DMX

Attempts:

3 left

💡 Hint

Common Mistakes

Using CNAME for alias records to AWS resources.

Using TXT or MX record types incorrectly.

Alias records to AWS resources like S3 website endpoints must use type A in Route 53.

4fill in blank

hard

Fill both blanks to create a health check that monitors an HTTP endpoint on port 80.

AWS

resource "aws_route53_health_check" "web_health" {
  type                = "[1]"
  resource_path       = "/"
  failure_threshold   = 3
  port                = [2]
  request_interval    = 30
  ip_address          = "192.0.2.44"
}

Drag options to blanks, or click blank then click option'

AHTTP

B80

CHTTPS

D443

Attempts:

3 left

💡 Hint

Common Mistakes

Using HTTPS type with port 80.

Using HTTP type with port 443.

The health check type for HTTP is HTTP and the port for HTTP is 80.

5fill in blank

hard

Fill all three blanks to create a Route 53 record that routes traffic to an Elastic Load Balancer.

AWS

resource "aws_route53_record" "elb_alias" {
  zone_id = aws_route53_zone.primary.zone_id
  name    = "app"
  type    = "[1]"
  alias {
    name                   = aws_lb.app.dns_name
    zone_id                = aws_lb.app.zone_id
    evaluate_target_health = [2]
  }
  ttl     = [3]
}

Drag options to blanks, or click blank then click option'

AA

Btrue

C300

DCNAME

Attempts:

3 left

💡 Hint

Common Mistakes

Using CNAME type for ELB alias records.

Setting evaluate_target_health to false when health checks are needed.

Using very high or zero TTL values.

Alias records to ELB use type A. The evaluate_target_health is usually set to true to check ELB health. TTL is commonly set to 300 seconds.

Practice

1. Why is DNS management important for a website?

easy

A. It controls the website's color and layout.

B. It connects the website name to the correct server IP address.

C. It stores the website's images and videos.

D. It manages user passwords and login details.

Solution

1. Step 1: Understand DNS role

   DNS translates a website's name into its server's IP address so browsers can find it.

2. Step 2: Identify correct function

   Only It connects the website name to the correct server IP address. describes this connection role; others describe unrelated tasks.

3. Final Answer:

   It connects the website name to the correct server IP address. -> Option B

4. Quick Check:

   DNS connects names to IPs = C [OK]

Hint: DNS links names to servers, not content or design [OK]

Common Mistakes:

• Confusing DNS with website content storage
• Thinking DNS manages website design
• Assuming DNS handles user data

2. Which DNS record type is used to point a domain to an IPv4 address?

easy

A. A record

B. TXT record

C. CNAME record

D. MX record

Solution

1. Step 1: Recall DNS record types

   An A record maps a domain to an IPv4 address.

2. Step 2: Match record to IP type

   MX is for mail, CNAME for aliases, TXT for text info; only A matches IPv4.

3. Final Answer:

   A record -> Option A

4. Quick Check:

   A record = IPv4 address mapping [OK]

Hint: A record = IPv4 address, MX = mail, CNAME = alias [OK]

Common Mistakes:

• Confusing MX with IP address record
• Using CNAME instead of A for IP
• Thinking TXT stores IP addresses

3. Given this AWS Route 53 DNS record configuration:

{"Name": "example.com.", "Type": "CNAME", "Value": "www.example.com."}

What happens when a user visits example.com?

medium

A. The browser shows an error page immediately.

B. The browser directly loads example.com without redirection.

C. The browser looks up www.example.com and loads that site.

D. The DNS lookup fails because CNAME cannot be used at the root domain.

Solution

1. Step 1: Understand CNAME restrictions

   CNAME records cannot be used at the root domain (example.com) in Route 53; only subdomains.

2. Step 2: Predict DNS behavior

   Using CNAME at root causes DNS lookup failure, so the browser cannot resolve example.com.

3. Final Answer:

   The DNS lookup fails because CNAME cannot be used at the root domain. -> Option D

4. Quick Check:

   CNAME at root domain = DNS failure [OK]

Hint: CNAME not allowed at root domain in Route 53 [OK]

Common Mistakes:

• Assuming CNAME works at root domain
• Thinking browser auto-fixes DNS errors
• Confusing CNAME with A record usage

4. You set an MX record in Route 53 but emails are not received. What is a common DNS mistake causing this?

medium

A. Using an A record instead of MX for mail routing.

B. Using a CNAME record for the mail server instead of MX.

C. Setting the MX record with a trailing dot missing in the domain name.

D. Setting TTL to zero for the MX record.

Solution

1. Step 1: Check MX record format

   MX records require fully qualified domain names ending with a dot to be valid.

2. Step 2: Identify common error

   Missing trailing dot causes DNS to treat the name as relative, breaking mail routing.

3. Final Answer:

   Setting the MX record with a trailing dot missing in the domain name. -> Option C

4. Quick Check:

   MX domain needs trailing dot [OK]

Hint: MX domain names must end with a dot in DNS records [OK]

Common Mistakes:

• Using A record for mail routing
• Omitting trailing dot in MX domain
• Confusing CNAME with MX record

5. You want to improve your website's reliability and security using DNS. Which AWS Route 53 feature helps by routing traffic to healthy endpoints automatically?

hard

A. Failover routing with health checks

B. Latency-based routing

C. Simple routing without health checks

D. Weighted routing without monitoring

Solution

1. Step 1: Understand routing types

   Failover routing uses health checks to route traffic only to healthy endpoints.

2. Step 2: Match feature to goal

   To improve reliability and security by avoiding unhealthy servers, failover routing is best.

3. Final Answer:

   Failover routing with health checks -> Option A

4. Quick Check:

   Failover routing + health checks = reliability [OK]

Hint: Use failover routing with health checks for reliability [OK]

Common Mistakes:

• Choosing routing without health checks
• Confusing latency routing with failover
• Ignoring health checks in routing