You can block PHP nobody spammers with the following steps. But make sure, you must have Apache 1.3x, PHP 4.3x and Exim. This may work on other systems but we have only tested it on a Cpanel/WHM Red Hat Enterprise system.
At first you have to Login to your server and su – to root.
Turn off exim while we do this so it doesn’t freak out.
Backup your original /usr/sbin/sendmail file. On systems using Exim MTA, the sendmail file is just basically a pointer to Exim itself.
mv /usr/sbin/sendmail /usr/sbin/sendmail.hidden