Listener rules and routing in AWS - Practice Problems & Coding Challenges

Challenge - 5 Problems

❓ service_behavior

intermediate

How does an ALB listener rule prioritize routing?

An Application Load Balancer (ALB) has multiple listener rules configured. How does the ALB decide which rule to apply when a request matches multiple rules?

A The ALB applies the rule with the highest priority number.

B The ALB applies the rule with the lowest priority number.

C The ALB applies the rule that was created most recently.

D The ALB applies all matching rules in parallel.

💡 Hint

Think about how priority numbers work in ordering rules.

Listener rules have priority numbers where lower numbers have higher priority. The ALB applies the rule with the lowest priority number that matches the request.

❓ Configuration

intermediate

Which listener rule configuration routes traffic to a target group for path '/images/*'?

You want to route all requests with paths starting with '/images/' to a specific target group. Which listener rule condition correctly matches this path pattern?

A Path pattern is '/images/*'

B Path is exactly '/images/*'

C Path is '/images/*' (wildcard supported)

D Host header is '/images/*'

💡 Hint

Listener rules use path patterns, not exact path or host header for this.

Listener rules use path pattern conditions to match URL paths with wildcards. The correct syntax is 'Path pattern is /images/*'.

❓ Architecture

advanced

What happens if no listener rule matches a request?

An ALB listener receives a request that does not match any configured listener rule. What is the expected behavior?

A The ALB retries the request on another listener.

B The ALB returns a 404 Not Found error to the client.

C The ALB drops the request without response.

D The ALB forwards the request to the default target group of the listener.

💡 Hint

Consider what the default target group is used for in a listener.

If no listener rule matches, the ALB forwards the request to the listener's default target group.

❓ security

advanced

Which listener rule condition can help restrict traffic to a specific domain?

You want to ensure your ALB only routes requests coming from 'example.com'. Which listener rule condition should you use?

A Host header condition with 'example.com'

B Source IP condition with 'example.com'

C Path pattern condition with '/example.com/*'

D HTTP method condition with 'example.com'

💡 Hint

Think about how domain names are represented in HTTP requests.

The host header condition matches the domain name in the HTTP request, so using 'Host header is example.com' restricts traffic to that domain.

✅ Best Practice

expert

How should you design listener rules for efficient routing with many path patterns?

You have an ALB with many path-based listener rules. What is the best practice to optimize routing performance and maintainability?

A Create one listener rule per path and assign the same priority to all.

B Use a single listener rule with a complex regex path pattern.

C Group related paths into fewer rules with clear, non-overlapping path patterns and use priority numbers carefully.

D Use many low-priority rules with overlapping path patterns.

💡 Hint

Think about how priority and rule clarity affect routing.

Grouping related paths into fewer, clear, non-overlapping rules with carefully assigned priorities improves routing efficiency and makes maintenance easier.