Odi's astoundingly incomplete notes
New entries | CodeRBL check in PHP
I am going to use blacklists for all the interactive parts on this website to get rid of comment spammers. If you would like to implement a similar thing, you can use the sample code blow:
function rbl_is_listed($ip, $rbl) { $comp = explode('.', $ip); if (sizeof($comp) != 4) die("Not a valid IPv4: $ip"); $revip = join('.',array_reverse($comp)); $result = gethostbyname("$revip.$rbl"); return ($result == '127.0.0.2'); } $ip = $_SERVER["REMOTE_ADDR"]; $rbl = 'bl.spamcop.net'; echo rbl_is_listed($ip,$rbl) ? 'listed' : 'not listed';
There are many DNS blacklists out there. Choose carefully.
Some use the last number as a status to explain the RBL listing reason. Perhaps look for the first 3 numbers:
127.0.0.