php mail form sends false mails

Question

I'm new to php and I have a form that needs to get information and send it to me by mail. The problem is that sometimes I receive email containing only an IP adress and nothing else. I tried pressing "send" without entering anything in the fields and I receive an email containing everything else but the answers to the questions, so that is not the case it seems. My questions is why do I receive email containing only an IP adress? Thanks!

<?php
    $to = "mail@gmail.com";
    $subject = "energiebio contact form: {$_POST['ams']['Destination']} ";
    $from = $_POST['ams']['E-mail'];
    $valid=1;
    $message ='';

    foreach ($_POST['mas'] as $k=>$v){
        if (trim($v)=='')$valid=0;
        $k = str_replace('_',' ',$k);
        $message .="$k : $v<br>";
    }

    $message .="<hr />IP: {$_SERVER['REMOTE_ADDR']}";

    function sndmail($from,$to,$subject,$message){
        $headers = "MIME-Version: 1.0\r\n";
        $headers .= "Content-type: text/html; charset=iso-8859-1\r\n";
        $headers .= "From:".$from ."\r\n";
        mail($to, $subject, $message, $headers);
    }

    if ($valid=='1') {
        sndmail($from,$to,$subject,$message);
        header( 'Location: http://site.ro/danke.html' ) ;
    }else header( 'Location: http://site.ro/error.html' ) ;
?>

I've discovered that it's the same IP and that I can't get a "whois" on it the same: 92.85.174.105

Answer 1

I'd say something, for example google bot or a spam bot, is hitting your email script without using your form. If you have HTML like this:

<form action="postmail.php">
<!-- stuff -->

a script can just hit your "postmail.php" without using the send button. Then body content would be empty, and you'd get an empty email containing nothing but the senders ip.