Return to Answer

So your location should look like

So your location should look like (wrong example! see the update to answer)

Update @ 2025.01.22

It turns out that two of the three configuration variants where the try_files directive was being used, contain mistakes regarding the usage of this directive.

The variant I proposed:

try_files /dev/null /index.php$is_args$args; 

will result in an internal redirection loop. Additionally, using /dev/null as the first parameter of the try_files directive offers no performance benefit, contrary to what is suggested here.

The variant proposed by @TeroKilkanen:

try_files /index.php$is_args$args =404; 

is closer to being correct. However, the $is_args and $args nginx variables should not be used in this context because they will be treated as part of the physical filename rather than the query string. Consequently, any request with a query string will fail with this configuration.

Moreover, the snippets/fastcgi-php.conf file (a configuration snippet packaged with nginx on Debian-based Linux distributions) contains the following:

# regex to split $uri to $fastcgi_script_name and $fastcgi_path fastcgi_split_path_info ^(.+\.php)(/.+)$; # Check that the PHP script exists before passing it try_files $fastcgi_script_name =404; # Bypass the fact that try_files resets $fastcgi_path_info # see: http://trac.nginx.org/nginx/ticket/321 set $path_info $fastcgi_path_info; fastcgi_param PATH_INFO $path_info; fastcgi_index index.php; include fastcgi.conf; 

If this snippet is included in the PHP location block that already contains a try_files directive, it will cause the following error during configuration validation at nginx startup:

nginx: [emerg] "try_files" directive is duplicate in ... 

That being said, there are two correct options to achieve the behavior the OP desires:

1. Using the try_files directive to additionally check an existence of the index.php file:

   location / { try_files /index.php =404; include fastcgi_params; fastcgi_param SCRIPT_FILENAME $request_filename; fastcgi_pass unix://var/run/php/php7.3-fpm.sock; } 

2. Skip the existence check for better performance explicitly specifying the PHP script filename (if you are certain that the index.php file always exists):

   location / { include fastcgi_params; fastcgi_param SCRIPT_FILENAME $document_root/index.php; fastcgi_pass unix://var/run/php/php7.3-fpm.sock; } 

   Or even explicitly specifying the full path to the index.php file (this way the root directive can be omitted al all):

   location / { include fastcgi_params; fastcgi_param SCRIPT_FILENAME /full/path/to/index.php; fastcgi_pass unix://var/run/php/php7.3-fpm.sock; } 

1. Location you used will match only the requests containing $ symbol, that's definitely not what you want.
2. Using the try_files directive you must specify at least one file/folder to check. The easiest way to specify the file that would fail the existence check is to specify dev/null.

So your location should look like

 location / { try_files /dev/null /index.php$is_args$args; include snippets/fastcgi-php.conf; fastcgi_pass unix://var/run/php/php7.3-fpm.sock; } 

1. Location you used will match only the requests containing $ symbol, that's definitely not what you want.
2. Using the try_files directive you must specify at least one file/folder to check. The easiest way to specify the file that would fail the existence check is to specify dev/null.

So your location should look like

 location / { try_files /dev/null /index.php$is_args$args; include fastcgi.conf; fastcgi_param SCRIPT_FILENAME $request_filename; fastcgi_pass unix://var/run/php/php7.3-fpm.sock; } 

or, without the try_files directive

 location / { include fastcgi.conf; fastcgi_param SCRIPT_FILENAME $document_root/index.php; fastcgi_pass unix://var/run/php/php7.3-fpm.sock; }