NGINX error: Conflicting server name – Two or more sites have the same server name

Understanding the NGINX Conflicting Server Name Error

The NGINX ‘Conflicting server name’ error occurs when two or more server blocks are defined with the same server_name directive. NGINX uses the server_name directive to differentiate between different domains or subdomains. When a request comes in, NGINX checks this directive to determine which server block should handle the request. If multiple blocks have the same server_name, NGINX can’t reliably route your users’ requests, hence the error.

Solutions to Fix NGINX Server Name Conflicts

Solution 1: Modify Server Configuration Files

This solution involves editing the NGINX server block configuration files to ensure that each site has a unique server_name.

1. Open the configuration file for each site using a text editor.
2. Locate the server_name directive in each server block.
3. Modify the server_name directive so that each server block has a unique name.
4. Save the changes and exit the text editor.
5. Test the new NGINX configuration by running nginx -t.
6. If there are no errors, reload NGINX with service nginx reload or systemctl reload nginx.

In this scenario, the solution involves configurations unique to your deployment.

Notes: This solution is direct and usually effective, but bear in mind that it requires access to and an understanding of NGINX configuration files. Additionally, care should be taken to ensure that the server names you provide do not conflict with other domains.

Solution 2: Consolidate Server Blocks

If the conflicting server names are intentionally pointing to the same content, you can consolidate the server blocks into a single block with multiple recognized names using the server_name directive.

1. Identify server blocks that are intended to serve the same content.
2. Merge these server blocks into one by using a single server_name directive with multiple names separated by spaces.
3. Remove the now redundant server block(s).
4. Save and close the file.
5. Run nginx -t to ensure your configuration is correct.
6. Reload NGINX with service nginx reload or systemctl reload nginx.

Here’s an example of what the consolidated server block might look like:

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

Notes: Consolidation is practical for managing domains and subdomains serving identical content. However, it should be applied judiciously, as overuse may lead to less readable and harder-to-maintain configurations.

Solution 3: Utilize Include Directive

The include directive can be used to split configuration into separate files, making it easier to manage and avoiding conflicts.

1. Create separate configuration files for each unique server block.
2. Include the new configuration files in the main NGINX configuration using the include directive.
3. Ensure that each included file does not have server blocks with overlapping server names.
4. Save the main configuration file.
5. Test the NGINX configuration with nginx -t.
6. Reload NGINX to apply the new configuration.

This is what the include directive might look like in your main configuration file:

http {
    ...
    include /etc/nginx/conf.d/*.conf;
    ...
}

Notes: The use of include directive allows for more manageable configuration files, especially for environments with a large number of server blocks. However, it also requires a disciplined naming and file organization system to prevent future conflicts.