PHP mail function on *nix plaform
Advance stuff
return-path rewrite
$mailFrom = "ValidMailbox@validdomain";
$mailTo = "ValidToAddress";
$mailSubject = "Useful Subject: Here's my subject";
$mailSignature = "\n\n--\n";
$mailSignature .= "Your friendly Neighborhood web application.\n";
$mailSignature .= "For help and other information, see http://yourwebapp/help\n";
$mailBody ="blahblahblah\n";
$mailBody .= $mailSignature;
$mailHeader = 'From: "'.$mailFrom.'" '."\r\n";
$mailHeader .= "Reply-To: $mailFrom\r\n";
$mailHeader .= "X-Mailer: ".MYSITE."\r\n";
$mailHeader .= "X-Sender-IP: {$_SERVER['REMOTE_ADDR']}\r\n";
$mailHeader .= "Bcc: ".MONITORADDRESS."\r\n";
$mailParams = "-f$mailFrom";
$mailResult = mail($mailTo,$mailSubject,$mailBody,$mailHeader,$mailParams);
Be aware of this $mailParams = “-f$mailFrom”;
in php.ini there is sendmail_path with default settings (for *nix): sendmail -t -i
read more at http://it.extension.org/wiki/Best_Practices_Using_the_PHP_mail_Function

