nginx trouble loading index file

Question

I have this nginx vhost file

server { # php/fastcgi
    listen       80;
    server_name  trinityplex.com www.trinity.com;
    access_log   /home/web/trinity_web/log/access.log;
    root /home/web/trinity_web/public;

    location / {
      index    index.html index.htm index.php;
    }
}

(for domain trinityplex.com), but if I go to trinityplex.com nginx display me 502 Bad gateway and throws the index file - chrome download index.php like a normal download.

It's ridiculous I have never seen that. If I ask PHP for version it dumps

PHP 5.3.5-0.dotdeb.0 with Suhosin-Patch (cli) (built: Jan  7 2011 00:30:52) 
Copyright (c) 1997-2009 The PHP Group
Zend Engine v2.3.0, Copyright (c) 1998-2010 Zend Technologies
    with Suhosin v0.9.32.1, Copyright (c) 2007-2010, by SektionEins GmbH

Have you any ideas how to fix that?

Here is an nginx cofig file

user root;
worker_processes  1;

events {
    worker_connections  1024;
}

http {
    include       mime.types;
    default_type  application/octet-stream;

    sendfile        on;

    keepalive_timeout  65;
    server_names_hash_bucket_size 128;

    gzip  on;

    include /usr/local/nginx/sites-enabled/*;

}

Answer 1

You haven't configured PHP in the server section so PHP files will obviously be sent as plain text. How are you planning to run PHP? As FastCGI?

Update: The configuration you have shown here does still not include anything at all about PHP or FastCGI. Try something like this:

        # pass the PHP scripts to FastCGI server listening on 127.0.0.1:9000
        #
        location ~ .php$ {
                fastcgi_pass   127.0.0.1:9000;
                fastcgi_param  SCRIPT_FILENAME $document_root$fastcgi_script_name;
                fastcgi_index  index.php;
                include        fastcgi_params;
        }