note 51555 added to function.mail

I have a website with a PHP contact form. The problem is that any one can send me email via contact form more than Thousand times. I want to restrict that spamming .. I know that if you use cookies in JSP it will restrict but in php I do not know Please help me Regards, David ---- Manual Page -- http://www.php.net/manual/en/function.mail.php Edit -- http://master.php.net/manage/user-notes.php?action=edit+51555 Delete: added to the manual -- http://master.php.net/manage/user-notes.php?action=delete+51555&report=yes&reason=added+to+the+manual Delete: bad code -- http://master.php.net/manage/user-notes.php?action=delete+51555&report=yes&reason=bad+code Delete: spam -- http://master.php.net/manage/user-notes.php?action=delete+51555&report=yes&reason=spam Delete: useless -- http://master.php.net/manage/user-notes.php?action=delete+51555&report=yes&reason=useless Delete: other reasons -- http://master.php.net/manage/user-notes.php?action=delete+51555&report=yes Reject -- http://master.php.net/manage/user-notes.php?action=reject+51555&report=yes Search -- http://master.php.net/manage/user-notes.php