HTTP/2 configuration in Nginx - Practice Problems & Coding Challenges

Challenge - 5 Problems

💻 Command Output

intermediate

Check if HTTP/2 is enabled on Nginx

You run the command curl -I --http2 https://example.com on a server with Nginx configured. What output line confirms HTTP/2 is enabled?

A HTTP/2 200

B HTTP/1.1 200 OK

C HTTP/3 200

D HTTP/1.0 200 OK

💡 Hint

Look for the HTTP version in the response headers.

The response line starting with 'HTTP/2' confirms the server responded using HTTP/2 protocol.

❓ Configuration

intermediate

Enable HTTP/2 in Nginx server block

Which Nginx server block directive correctly enables HTTP/2 for HTTPS?

A listen 443 ssl http2;

B listen 443 ssl;

C listen 443 http2;

D listen 80 http2;

💡 Hint

HTTP/2 requires SSL and the correct listen directive.

The directive 'listen 443 ssl http2;' enables SSL and HTTP/2 on port 443.

❓ Troubleshoot

advanced

Why is HTTP/2 not working despite configuration?

You configured Nginx with listen 443 ssl http2; but HTTP/2 is not working. Which is the most likely cause?

A Not setting server_name directive

B Using port 80 instead of 443

C Not enabling gzip compression

D Missing valid SSL certificate and key files

💡 Hint

HTTP/2 requires a secure connection.

HTTP/2 over Nginx requires SSL with valid certificates; missing them disables HTTP/2.

✅ Best Practice

advanced

Recommended TLS versions for HTTP/2 in Nginx

Which TLS versions should you enable in Nginx to support HTTP/2 securely?

A TLSv1.0, TLSv1.1, TLSv1.2

B TLSv1.0 and TLSv1.1 only

C TLSv1.2 and TLSv1.3 only

D SSLv3 and TLSv1.2

💡 Hint

Older TLS versions are insecure and not recommended.

TLSv1.2 and TLSv1.3 are secure and recommended for HTTP/2 support.

🔀 Workflow

expert

Order steps to enable HTTP/2 on Nginx with SSL

Put these steps in the correct order to enable HTTP/2 on an Nginx server with SSL:

A 2,1,4,3

B 1,4,2,3

C 1,2,4,3

D 4,1,2,3

💡 Hint

Think about getting certificates before configuring paths.

First get certificates, then configure paths, enable HTTP/2 in listen, then reload Nginx.

Practice

1. What is the correct way to enable HTTP/2 in an nginx server block?

easy

A. Add http2 to the location block

B. Add http2 to the server_name directive

C. Add http2 to the listen directive with SSL enabled

D. Add http2 to the root directive

Solution

1. Step 1: Understand HTTP/2 enabling in nginx

   HTTP/2 is enabled by adding the http2 parameter to the listen directive, which must be used with SSL (HTTPS).

2. Step 2: Identify correct directive usage

   The http2 parameter does not belong in server_name, root, or location blocks.

3. Final Answer:

   Add http2 to the listen directive with SSL enabled -> Option C

4. Quick Check:

   Enable HTTP/2 by adding http2 to listen with SSL [OK]

Hint: Add 'http2' only in listen directive with SSL [OK]

Common Mistakes:

• Adding http2 to server_name or root directives
• Forgetting to enable SSL when using http2
• Placing http2 inside location blocks

2. Which of the following is the correct syntax to enable HTTP/2 on port 443 in nginx?

easy

A. listen 443 ssl;

B. listen http2 443 ssl;

C. listen 443 http2;

D. listen 443 ssl http2;

Solution

1. Step 1: Review nginx listen directive syntax

   The correct order is listen [port] ssl http2; to enable SSL and HTTP/2 on the port.

2. Step 2: Check each option

   listen 443 ssl http2; uses correct syntax: listen 443 ssl http2;. listen http2 443 ssl; reverses order but is invalid. listen 443 ssl; misses http2. listen 443 http2; misses ssl, which is required for http2.

3. Final Answer:

   listen 443 ssl http2; -> Option D

4. Quick Check:

   Correct syntax is 'listen 443 ssl http2;' [OK]

Hint: Use 'listen 443 ssl http2;' exactly for HTTP/2 [OK]

Common Mistakes:

• Omitting ssl when enabling http2
• Placing http2 before ssl in listen directive
• Using http2 without SSL on port 443

3. Given this nginx server block snippet, what will happen when a client connects?

server {
    listen 443 ssl http2;
    ssl_certificate /etc/ssl/cert.pem;
    ssl_certificate_key /etc/ssl/key.pem;
    server_name example.com;
}

medium

A. The server will accept HTTPS connections using HTTP/2 protocol

B. The server will accept HTTP connections only, no HTTP/2

C. The server will reject connections due to missing http2 directive

D. The server will accept HTTPS but use HTTP/1.1 only

Solution

1. Step 1: Analyze listen directive

   The listen directive includes ssl and http2, enabling HTTPS with HTTP/2 support.

2. Step 2: Confirm SSL certificates presence

   SSL certificate and key files are specified, so HTTPS can work properly.

3. Final Answer:

   The server will accept HTTPS connections using HTTP/2 protocol -> Option A

4. Quick Check:

   listen with ssl and http2 means HTTPS + HTTP/2 enabled [OK]

Hint: ssl + http2 in listen means HTTPS with HTTP/2 [OK]

Common Mistakes:

• Assuming HTTP/2 works without ssl
• Confusing HTTP and HTTPS ports
• Ignoring the http2 parameter in listen

4. You added http2 to your nginx listen directive but HTTP/2 is not working. Which configuration mistake could cause this?

medium

A. Forgetting to enable SSL (missing ssl in listen directive)

B. Using http2 in the server_name directive

C. Setting listen to port 80 with http2

D. Adding http2 inside the location block

Solution

1. Step 1: Understand HTTP/2 requirements in nginx

   HTTP/2 requires SSL (HTTPS) to be enabled in nginx; without ssl in the listen directive, HTTP/2 won't work.

2. Step 2: Evaluate other options

   Options A, C, and D are invalid uses of http2 but the main cause is missing SSL.

3. Final Answer:

   Forgetting to enable SSL (missing ssl in listen directive) -> Option A

4. Quick Check:

   HTTP/2 needs SSL enabled in listen directive [OK]

Hint: Always include ssl with http2 in listen directive [OK]

Common Mistakes:

• Not enabling ssl with http2
• Placing http2 in wrong directives
• Trying http2 on port 80 without ssl

5. You want to configure nginx to serve HTTP/2 on port 443 and redirect all HTTP (port 80) traffic to HTTPS. Which configuration snippet correctly achieves this?

hard

A. server {
listen 80 http2;
return 301 https://$host$request_uri;
}

server {
listen 443 ssl;
server_name example.com;
}

B. server {
listen 80;
return 301 https://$host$request_uri;
}

server {
listen 443 ssl http2;
ssl_certificate /etc/ssl/cert.pem;
ssl_certificate_key /etc/ssl/key.pem;
server_name example.com;
}

C. server {
listen 443 ssl http2;
server_name example.com;
}

server {
listen 80 ssl http2;
return 301 https://$host$request_uri;
}

D. server {
listen 443 ssl;
ssl_certificate /etc/ssl/cert.pem;
ssl_certificate_key /etc/ssl/key.pem;
server_name example.com;
}

server {
listen 80;
return 301 https://$host$request_uri;
}

Solution

1. Step 1: Redirect HTTP to HTTPS on port 80

   The first server block listens on port 80 without SSL and redirects all requests to HTTPS using a 301 redirect.

2. Step 2: Enable HTTPS with HTTP/2 on port 443

   The second server block listens on port 443 with ssl and http2 enabled, and specifies SSL certificates.

3. Step 3: Verify other options

   server {
       listen 80 http2;
       return 301 https://$host$request_uri;
   }
   
   server {
       listen 443 ssl;
       server_name example.com;
   }

   incorrectly enables http2 on port 80 (no SSL).

   server {
       listen 443 ssl http2;
       server_name example.com;
   }
   
   server {
       listen 80 ssl http2;
       return 301 https://$host$request_uri;
   }

   enables SSL and http2 on port 80 which is invalid.

   server {
       listen 443 ssl;
       ssl_certificate /etc/ssl/cert.pem;
       ssl_certificate_key /etc/ssl/key.pem;
       server_name example.com;
   }
   
   server {
       listen 80;
       return 301 https://$host$request_uri;
   }

   misses http2 on port 443.

4. Final Answer:

   The configuration correctly redirects HTTP to HTTPS and enables HTTP/2 on HTTPS -> Option B

5. Quick Check:

   Redirect HTTP on 80, enable SSL+http2 on 443 [OK]

Hint: Redirect HTTP on 80, enable SSL+http2 on 443 [OK]

Common Mistakes:

• Enabling http2 on port 80 without SSL
• Missing http2 on HTTPS server block
• Not redirecting HTTP to HTTPS properly