OSTicket

http://osticket.com/

SSL setup isn't required, but I'd recommend it.

user  nginx;
worker_processes 1;
 
events {
    worker_connections  1024;
}
 
http {
    include         mime.types;
    default_type    application/octet-stream;
    sendfile        on;
    charset         utf-8;
    gzip            on;
    gzip_types      text/plain application/xml text/javascript;
    gzip_min_length 1000;
 
    server {
        listen 80;
        rewrite ^ https://tickets.mydomain.com permanent;
    }
 
    server {
        server_name  tickets.mydomain.com;
        listen       443;
        ssl on;
        ssl_certificate      /etc/nginx/certs/cert.pem;
        ssl_certificate_key  /etc/nginx/certs/cert.key;
 
        keepalive_timeout 70;
 
        root /var/www/osticket;
 
        location / {
            index index.php;
            try_files $uri $uri/ index.php;
        }
 
        location ~ \.php$ {
            fastcgi_pass   127.0.0.1:8888;
            fastcgi_index  index.php;
            fastcgi_param  SCRIPT_FILENAME  $document_root$fastcgi_script_name;
            include        fastcgi_params;
        }
    }
}