If you would like to have quick site check tool on your website and give your users the ability to check the accessibility of different ports and services right from your website you may use our Free PHP Site Check Tool.
PHP Site Check functionality
Easy to install and almost no configuration required the script can check availability of HTTP (80), FTP (21), SMTP (25) and POP3 (110) ports from your location. You may try the DEMO below. To check the service please indicate the host name and select necessary checkboxes.
PHP Site Check Script DEMO