Wildcard and regex server names in Nginx - Mini Project: Build & Apply

Wildcard and Regex Server Names in Nginx

📖 Scenario: You are setting up a web server using Nginx. Your goal is to configure server blocks that respond to different website names. Some websites use exact names, some use wildcard patterns, and some use regular expressions to match multiple subdomains.

🎯 Goal: Build an Nginx configuration with three server blocks: one for an exact domain, one using a wildcard server name, and one using a regex server name.

📋 What You'll Learn

Create a server block with an exact server name example.com

Add a server block with a wildcard server name matching all subdomains of example.org

Add a server block with a regex server name matching any subdomain starting with test and ending with .net

Print the full Nginx configuration to verify the setup

💡 Why This Matters

🌍 Real World

Web servers often need to handle many domain names and subdomains. Using wildcard and regex server names in Nginx helps manage these efficiently.

💼 Career

Understanding Nginx server name configuration is essential for DevOps roles managing web infrastructure and deployments.

1

Create exact server name block

Create a server block with server_name example.com; and listen on port 80. Use root /var/www/example.com; inside the block.

Nginx

# Your code here

Hint

Use server { ... } block with listen 80; and server_name example.com;.

2

Add wildcard server name block

Add a new server block below the first one with server_name *.example.org; and listen on port 80. Use root /var/www/wildcard; inside this block.

Nginx

server {
    listen 80;
    server_name example.com;
    root /var/www/example.com;
}

# Your code here

Hint

Use server_name *.example.org; to match all subdomains of example.org.

3

Add regex server name block

Add a third server block with server_name ~^test.*\.net$; to match any subdomain starting with test and ending with .net. Listen on port 80 and set root /var/www/regex;.

Nginx

server {
    listen 80;
    server_name example.com;
    root /var/www/example.com;
}

server {
    listen 80;
    server_name *.example.org;
    root /var/www/wildcard;
}

# Your code here

Hint

Use server_name ~^test.*\.net$; for regex matching. Remember to escape the dot.

4

Print the full Nginx configuration

Print the full Nginx configuration by outputting the combined server blocks exactly as written.

Nginx

server {
    listen 80;
    server_name example.com;
    root /var/www/example.com;
}

server {
    listen 80;
    server_name *.example.org;
    root /var/www/wildcard;
}

server {
    listen 80;
    server_name ~^test.*\.net$;
    root /var/www/regex;
}

# Your code here

Hint

Use a print statement to output the full configuration exactly as written.

Practice

1. What does a wildcard server name like *.example.com match in nginx?

easy

A. Any domain ending with example.com, including example.com itself

B. Only the exact domain example.com

C. Any subdomain of example.com, like blog.example.com or shop.example.com

D. Only domains starting with a star character

Solution

1. Step 1: Understand wildcard usage in server names

   A wildcard * before a domain matches any subdomain part, but not the root domain itself.

2. Step 2: Apply to *.example.com

   This matches domains like blog.example.com or shop.example.com, but not example.com alone.

3. Final Answer:

   Any subdomain of example.com, like blog.example.com or shop.example.com -> Option C

4. Quick Check:

   Wildcard * matches subdomains only [OK]

Hint: Wildcard * matches subdomains, not the root domain [OK]

Common Mistakes:

• Thinking wildcard matches the root domain
• Confusing wildcard with regex syntax
• Assuming wildcard matches any domain ending

2. Which of the following is the correct syntax to define a regex server name in nginx?

easy

A. server_name /www\d+\.example\.com/;

B. server_name *example.com;

C. server_name ^www\d+\.example\.com$;

D. server_name ~^www\d+\.example\.com$;

Solution

1. Step 1: Recall regex server name syntax in nginx

   Regex server names start with a tilde ~ followed by the regex pattern.

2. Step 2: Check each option

   server_name ~^www\d+\.example\.com$; uses ~^www\d+\.example\.com$ which is correct regex syntax. Others either miss the tilde or use invalid delimiters.

3. Final Answer:

   server_name ~^www\d+\.example\.com$; -> Option D

4. Quick Check:

   Regex server names start with ~ [OK]

Hint: Regex server names always start with ~ in nginx [OK]

Common Mistakes:

• Omitting the ~ before regex pattern
• Using * instead of ~ for regex
• Using slashes / / as regex delimiters

3. Given this nginx config snippet:

server {
  server_name ~^www\d+\.example\.com$;
  return 200 'Matched regex server name';
}

What will be the response for a request to www12.example.com?

medium

A. Matched regex server name

B. 500 Internal Server Error

C. 404 Not Found

D. Default nginx welcome page

Solution

1. Step 1: Understand the regex pattern

   The regex ^www\d+\.example\.com$ matches domains starting with 'www' followed by one or more digits, then '.example.com'.

2. Step 2: Check if 'www12.example.com' matches

   'www12.example.com' matches the pattern because '12' are digits after 'www'.

3. Final Answer:

   Matched regex server name -> Option A

4. Quick Check:

   Regex matches www12.example.com [OK]

Hint: Check if domain fits regex pattern exactly [OK]

Common Mistakes:

• Assuming regex matches partial strings
• Ignoring start ^ and end $ anchors
• Confusing regex with wildcard matching

4. You wrote this nginx config:

server {
  server_name ~www\d+\.example\.com$;
  return 200 'Hello';
}

Why is this regex server_name directive incorrect?

medium

A. Missing ^ anchor at start of regex

B. Regex server name must start with ~ and pattern must start with ^

C. Regex pattern missing delimiters like / /

D. Regex server name must start with ~ and pattern must be valid

Solution

1. Step 1: Check regex server_name syntax

   Regex server names must start with ~ and the pattern should start with ^ to match from the beginning.

2. Step 2: Identify missing ^ anchor

   The pattern www\d+\.example\.com$ lacks the ^ anchor, causing partial matches rather than full hostname matches.

3. Final Answer:

   Regex server name must start with ~ and pattern must start with ^ -> Option B

4. Quick Check:

   Regex patterns need ^ anchor at start [OK]

Hint: Regex patterns should start with ^ for nginx server_name [OK]

Common Mistakes:

• Omitting ^ anchor in regex pattern
• Thinking delimiters like / / are needed
• Ignoring nginx error messages about regex

5. You want nginx to serve requests for any subdomain of example.com except www.example.com. Which server_name config achieves this?

hard

A. server_name ~^(?!www\.)[^.]+\.example\.com$;

B. server_name *.example.com www.example.com;

C. server_name ~^www\d+\.example\.com$;

D. server_name example.com *.example.com;

Solution

1. Step 1: Understand the requirement

   We want to match any subdomain except 'www.example.com'. This requires a regex with negative lookahead.

2. Step 2: Analyze options

   server_name ~^(?!www\.)[^.]+\.example\.com$; uses ~^(?!www\.)[^.]+\.example\.com$ which matches any subdomain not starting with 'www.'. Others either include 'www' or don't exclude it.

3. Final Answer:

   server_name ~^(?!www\.)[^.]+\.example\.com$; -> Option A

4. Quick Check:

   Negative lookahead excludes www subdomain [OK]

Hint: Use negative lookahead in regex to exclude specific subdomains [OK]

Common Mistakes:

• Using wildcard that includes www.example.com
• Not using regex for exclusion
• Confusing wildcard and regex syntax