The Problem
Setting up NGINX with SSL (Secure Sockets Layer) is a common task for any web administrator or developer wanting to secure traffic to a web server. However, encountering errors during this process can be discouraging, especially ones related to SSL configuration like the No ‘ssl_certificate’ is defined in server listening on SSL port error message. This guide will showcase how to troubleshoot and resolve this issue efficiently.
Why does it occur?
The mentioned error typically arises when NGINX cannot locate the SSL certificate or key within its configuration, which is deemed necessary for establishing a secure HTTPS connection. The NGINX server throws this error when it is instructed to listen on the SSL port (usually 443) but doesn’t have the required ssl_certificate and ssl_certificate_key directives properly set in its configuration file.
Steps to Fix the Error
Step 1: Verifying The SSL Certificate and Key
Before diving into NGINX configuration, ensure that the SSL certificate (.crt) and private key (.key) files are present on your file system and that their permissions are set correctly, allowing the NGINX process to read them.
$ ls -l /etc/ssl/certs/your_domain.crt
$ ls -l /etc/ssl/private/your_domain.key
If these commands do not return the files or indicate incorrect permissions, you will need to correct these issues before proceeding to configure NGINX.
Step 2: Configuring NGINX to Use SSL
Locate your NGINX configuration file. This could either be the default config file located at /etc/nginx/nginx.conf, /etc/nginx/sites-available/default, or any other custom configuration files you’ve set up in the /etc/nginx/conf.d folder.
$ nano /etc/nginx/sites-available/default
The following is a basic example of what a server block with SSL certificate directives might look like:
server {
listen 443 ssl;
server_name your_domain.com;
ssl_certificate /etc/ssl/certs/your_domain.crt;
ssl_certificate_key /etc/ssl/private/your_domain.key;
#rest of your configuration
}
Replace your_domain.com with your actual domain name, and adjust the file paths to point to your actual SSL certificate and key files.
Step 3: Checking SSL Configuration
NGINX ships with a handy tool to test the configuration files for syntax errors:
$ nginx -t
If you see any errors related to SSL after running this command, ensure all file paths are correct, file permissions are set properly, and there are no typos in the configuration.
Step 4: Reloading NGINX
Once the SSL certificate and key paths are correctly configured, and the syntax test passes, reload the NGINX configuration to apply the changes:
$ systemctl reload nginx
If the service reloads without error, your SSL should now be working correctly. You can verify by visiting https://your_domain.com and checking for a secure connection indication.
Additional Troubleshooting Tips
- Ensure you’re not referencing SSL certificates within a virtual host that’s not set to listen on 443 with ssl.
- Check if you have multiple NGINX server blocks competing on the same port and host which might not both be set up with SSL correctly.
- If you’re using a chain certificate (required when intermediate certificates are provided by your CA), make sure the intermediate certificates are appended properly to the primary certificate file.
Additionally, using cert tools such as openssl can verify that your SSL certificate matches your private key:
$ openssl x509 -noout -modulus -in /etc/ssl/certs/your_domain.crt | openssl md5
$ openssl rsa -noout -modulus -in /etc/ssl/private/your_domain.key | openssl md5
Both commands should return the same MD5 hash if everything is set up correctly.
FTP Corrected Files
If you made your SSL certificate and key on a different machine, you’ll need to upload them to your server. Ensure these files are uploaded to the correct location, and their permissions are secured using FTP or SCP.
Conclusion
Having an SSL enabled website is critical for security and is often necessary for SEO and customer confidence. Problems related to SSL configuration can be fixed with careful examination of configuration files and a clear understanding of how NGINX utilizes SSL certificates. By following the steps outlined in this analysis of the No ‘ssl_certificate’ is defined in server listening on SSL port error, you should be able to achieve a successful and secure NGINX configuration.
Remember that web security is an evolving field, and staying informed about best practices and new releases from software maintainers like the NGINX team is essential for maintaining a robust security posture.
