WAF, API Gateway, Load Balancer (Reverse Proxy)

Question 1

Is the load balancer a forward proxy or a reverse proxy?

Answer 1

Reverse Proxy

Question 2

Two available software load balancers in the market?

Answer 2

HAProxy
NGINX

Question 3

List four key features provided by API Gateway.

Answer 3

User Authentication & Authorization
API Rate Limiting
Request & Response Modifications
Response Caching

Question 4

List two key features provided by Load Balancer.

Answer 4

SSH Termination
Request Routing based on
- load
- response time
- API endpoint
- round-robin
- weighted (server size)

Question 5

How to prevent DDoS attacks on the web application?

Answer 5

WAF (Web Access Firewall) or AWS Shield

Question 6

Which rate limit algorithm to choose when the server doesn’t want to entertain bursts of traffic?

Answer 6

Leaky Bucket (use FIFO queue to hold requests)
Downside: High latency
Users: Shopify

Question 7

List five available rate-limiting algorithms.

Answer 7

Leaky Bucket (burst free)
Fixed Window Counter
Token Bucket
Sliding Windows Log (high on memory demand)
Sliding Window Counter (approximated)