In order to connect to your Intermedia mail server with the PHP mail() function or other mail-related functions, you must set local environment variables to override the default values of "SMTP" and "sendmail_from" like so:

    $retval = ini_set("SMTP", "");
    if (!$retval) { print "Could not set SMTP!<br>\n"; }

    $retval = ini_set("sendmail_from", "");
    if (!$retval) { print "Could not set sendmail_from!<br>\n"; }

Note: Please make sure that relay conditions are met.