#-#############################################
sub check_bl_data { 
#-############################################# 
    my $rev_ip = join('.', reverse(split(/\./, $ENV{'REMOTE_ADDR'})));
    my ($query, $result, $result_ip);
    local $_;
    
    my @rbls = (
        'blacklist.spambag.org',
        'cbl.abuseat.org',
        'cbl.anti-spam.org.cn',
        'cdl.anti-spam.org.cn',
        'dialup.blacklist.jippg.org',
        'dnsbl.ahbl.org',
        'dnsbl.cyberlogic.net',
        'dnsbl.sorbs.net',
        'dul.dnsbl.sorbs.net',
        'http.dnsbl.sorbs.net',        
        'ix-dns01.dnsbl.manitu.net',
        'ipwhois.rfc-ignorant.org',
        'korea.services.net',
        'problems.dnsbl.sorbs.net',
        'safe.dnsbl.sorbs.net',
        'socks.dnsbl.sorbs.net',
        'spamips.rbl.shub-inter.net',
        'spamtrap.drbl.drand.net',
        'web.dnsbl.sorbs.net',
        'xbl.spamhouse.org',
        'sbl.spamhouse.org',
    );
    
        foreach (@rbls) {
            $query = "$rev_ip.$_";                    
            $result = gethostbyname($query) || undef;
            
            defined $result && do {
                ($result_ip) = unpack('C4', $result);            
                $result_ip == 127 && error('bl-listed', $_);
            };
            
            undef $query;
            undef $result;
        }    
}