After setting up an environment with Nginx 0.8.54, PHP-FPM (PHP 5.3.2), and MySQL, PHP files aren't being processed while static HTML files work perfectly. The most telling symptom is that accessing PHP files returns a 404 error with PHP headers, suggesting the request reaches PHP-FPM but fails to execute properly.

The current Nginx PHP location block configuration:

location ~ \\.php$ {
    fastcgi_pass 127.0.0.1:9000;
    fastcgi_index index.php;
    fastcgi_param SCRIPT_FILENAME /var/www/eman/$fastcgi_script_name;
    include fastcgi_params;
}

And the fastcgi parameters:

fastcgi_connect_timeout 60;
fastcgi_send_timeout 180;
fastcgi_read_timeout 180;
fastcgi_buffer_size 128k;
fastcgi_buffers 4 256k;
fastcgi_busy_buffers_size 256k;
fastcgi_temp_file_write_size 256k;
fastcgi_intercept_errors on;

Several potential problems emerge from this configuration:

• The SCRIPT_FILENAME path might not match the actual document root
• Missing essential PHP-FPM pool configuration checks
• Potential file permission issues
• Possible socket vs TCP port communication mismatch

Here's an improved configuration that addresses these issues:

# First, define your root directory at server level
root /var/www/eman;

location ~ \\.php$ {
    try_files $uri =404;
    fastcgi_pass unix:/var/run/php5-fpm.sock; # Using Unix socket
    fastcgi_index index.php;
    fastcgi_param SCRIPT_FILENAME $document_root$fastcgi_script_name;
    include fastcgi_params;
    
    # Additional security parameters
    fastcgi_param PATH_INFO $fastcgi_script_name;
    fastcgi_param HTTP_PROXY "";
    fastcgi_param REMOTE_ADDR $remote_addr;
}

After implementing these changes:

1. Create a test PHP file: echo "<?php phpinfo(); ?>" > /var/www/eman/info.php
2. Set proper permissions: chown -R www-data:www-data /var/www/eman
3. Check PHP-FPM pool configuration matches socket/port settings
4. Test connectivity: curl -I http://localhost/info.php

If issues persist:

1. Check Nginx error logs: tail -f /var/log/nginx/error.log
2. Verify PHP-FPM is running: ps aux | grep php-fpm
3. Test PHP-FPM directly: SCRIPT_NAME=/info.php SCRIPT_FILENAME=/var/www/eman/info.php REQUEST_METHOD=GET cgi-fcgi -bind -connect 127.0.0.1:9000
4. Confirm file existence and permissions

For production environments, consider these enhancements:

location ~ [^/]\\.php(/|$) {
    fastcgi_split_path_info ^(.+?\\.php)(/.*)$;
    if (!-f $document_root$fastcgi_script_name) {
        return 404;
    }
    
    fastcgi_pass php-fpm;
    include fastcgi.conf;
    
    # Mitigate security issues
    fastcgi_param SCRIPT_FILENAME $realpath_root$fastcgi_script_name;
    fastcgi_param DOCUMENT_ROOT $realpath_root;
}

Remember to restart both services after changes:

service nginx restart
service php5-fpm restart

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When setting up a new Nginx + PHP-FPM stack, one of the most common issues is PHP files not being processed correctly. Here's what we typically observe:

- HTML files serve normally
- PHP files either return blank pages or 404 errors
- PHP files don't trigger standard Nginx 404 pages
- Server headers may show PHP version (indicating some PHP processing)

The core issue usually lies in the PHP handler configuration. Let's examine the critical components:

location ~ \.php$ {
    fastcgi_pass 127.0.0.1:9000;
    fastcgi_index index.php;
    fastcgi_param SCRIPT_FILENAME /var/www/eman/$fastcgi_script_name;
    include fastcgi_params;
}

1. Path Resolution Issues

The most frequent culprit is incorrect SCRIPT_FILENAME:

# Problematic:
fastcgi_param SCRIPT_FILENAME /var/www/eman/$fastcgi_script_name;

# Recommended:
fastcgi_param SCRIPT_FILENAME $document_root$fastcgi_script_name;

2. Socket vs Port Configuration

Verify your PHP-FPM is listening on the correct interface:

# Check PHP-FPM config (typically in /etc/php/fpm/pool.d/www.conf)
listen = 127.0.0.1:9000
# OR
listen = /var/run/php-fpm.sock

# Corresponding Nginx config:
fastcgi_pass 127.0.0.1:9000;
# OR for sockets:
fastcgi_pass unix:/var/run/php-fpm.sock;

3. File Permissions

PHP-FPM worker must have read access to the files:

chown -R www-data:www-data /var/www/eman
find /var/www/eman -type d -exec chmod 755 {} \;
find /var/www/eman -type f -exec chmod 644 {} \;

1. Verify PHP-FPM Status

systemctl status php-fpm
journalctl -u php-fpm --no-pager -n 20

2. Test PHP Processing Directly

Create a test script:

# /var/www/eman/info.php
<?php phpinfo(); ?>

3. Network Connectivity Check

netstat -tulnp | grep 9000
telnet 127.0.0.1 9000
curl -I http://localhost/info.php

Here's a verified working configuration:

server {
    listen 80;
    server_name eman.id.au;
    root /var/www/eman;
    index index.php index.html;

    location / {
        try_files $uri $uri/ =404;
    }

    location ~ \.php$ {
        include snippets/fastcgi-php.conf;
        fastcgi_pass unix:/var/run/php/php7.4-fpm.sock;
        fastcgi_param SCRIPT_FILENAME $document_root$fastcgi_script_name;
        include fastcgi_params;
    }

    location ~ /\.ht {
        deny all;
    }
}

• Verify PHP-FPM service is running
• Confirm Nginx and PHP-FPM use matching connection methods
• Check SELinux/AppArmor permissions if applicable
• Ensure all config changes are followed by service reloads