The following example helps you to check the IP Address is blacklisted.
<?php function is_blacklisted($ip) { $dnsbl_check=array("bl.spamcop.net", "relays.osirusoft.com", "list.dsbl.org", "sbl.spamhaus.org", "bl.nszones.com", "block.dnsbl.sorbs.net", "dnsbl-2.uceprotect.net", "dnsbl-3.uceprotect.net", "dnsbl.anticaptcha.net", "dyn.nszones.com" "..." ); $listed = ''; if ($ip) { $quads=explode(".",$ip); $rip=$quads[3].".".$quads[2].".".$quads[1].".".$quads[0]; for ($i=0; $i<count($dnsbl_check); $i++) { if (checkdnsrr($rip.".".$dnsbl_check[$i],"A")) { $listed.=$dnsbl_check[$i]." "; echo $dnsbl_check[$i]."<br>"; } } if ($listed) { return $listed; } else { return FALSE; } } } is_blacklisted('IP_ADDRESS'); ?>