Wildcard and regex server names in Nginx - Practice Problems & Coding Challenges

Challenge - 5 Problems

💻 Command Output

intermediate

Nginx server block matching with wildcard

Given the following nginx server block, what hostname will it match?

Nginx

server {
    server_name *.example.com;
    listen 80;
}

A example.com

B api.example.com

C sub.api.example.com

D example.net

💡 Hint

Remember that *.example.com matches one subdomain level only.

The wildcard *.example.com matches any single subdomain like api.example.com, but not the root domain example.com or multiple subdomain levels like sub.api.example.com.

💻 Command Output

intermediate

Regex server_name matching in nginx

What hostname will this nginx server block match?

Nginx

server {
    server_name ~^www\.(.+)\.example\.com$;
    listen 80;
}

A www.api.example.com

B www.example.com

C api.example.com

D www.api.example.net

💡 Hint

The regex matches hostnames starting with www. and ending with .example.com.

The regex ^www\.(.+)\.example\.com$ matches hostnames like www.api.example.com but not api.example.com (missing www), www.example.com (missing subdomain between www and example), or www.api.example.net (wrong domain).

❓ Configuration

advanced

Correct nginx server_name for multiple subdomains

Which server_name directive correctly matches any subdomain of example.com, including multiple levels like sub.api.example.com?

A server_name ~^www\.(.+)\.example\.com$;

B server_name *.example.com;

C server_name example.com *.example.com;

D server_name ~^(.+\.)?example\.com$;

💡 Hint

Think about how to match zero or more subdomain levels with regex.

The regex ~^(.+\.)?example\.com$ matches example.com and any subdomain including multiple levels like sub.api.example.com. The wildcard *.example.com only matches one subdomain level.

❓ Troubleshoot

advanced

Why does this nginx server block not match the hostname?

You configured this server block: server { server_name *.example.com; listen 80; } But requests to example.com are not handled by this block. Why?

A The server_name directive requires quotes around the wildcard

B The listen directive is missing the IP address

C The wildcard does not match the root domain without subdomain

D The server block must include a regex to match example.com

💡 Hint

Think about what *.example.com matches.

The wildcard *.example.com matches only subdomains like api.example.com. It does not match the root domain example.com itself, so requests to example.com are not handled by this block.

✅ Best Practice

expert

Choosing server_name order for overlapping patterns

You have these server blocks: 1) server_name example.com; 2) server_name *.example.com; 3) server_name ~^www\.(.+)\.example\.com$; Which order should nginx evaluate these to ensure the most specific matches are used first?

A Exact match first, then wildcard, then regex

B Regex server_name first, then wildcard, then exact match

C Exact match first, then regex, then wildcard

D Wildcard first, then exact match, then regex

💡 Hint

Exact matches have highest priority, regex lowest.

Nginx prioritizes server_name matches in this order: exact names first, then longest wildcard starting with an asterisk, then longest wildcard ending with an asterisk, and finally regex matches. So exact match example.com should be first, then wildcard, then regex.