本节分享的这段php代码，它适用于ISP的电子邮件服务提供商运行垃圾邮件的RBL检查，用获取到的IP地址，比对被列入黑名单的CBL。
当给定一个IP列表，或一个包含IP列表的文件时，利用DNSBL库核对某IP地址是否在黑名单中，

首先，需要下载或安装NET_DNSBL模块。
这个大家到pear库中查找下载即可，这是就不提供下载地址了。

代码：
 

说明：
以上脚本可以很容易的修改与扩展，IP数据可以来源于数据库，或GET、Post方式提交的数据。

附，反垃圾邮件组织域名表。
 

php与mysql结合实现的标签云效果，完整代码，如下：

<?php
/**
* php与mysql实现的标签云效果
* by www.
*/
$db_host = "localhost";
$db_user = "db_user";
$db_pass = "pass";
$db_name = "db_name";

mysql_connect($db_host, $db_user, $db_pass) or die(mysql_error());
mysql_select_db($db_name);

function tag_info() { 
  $result = mysql_query("SELECT * FROM tags GROUP BY tag ORDER BY count DESC"); 
  while($row = mysql_fetch_array($result)) { 
    $arr[$row['tag']] = $row['count'];
  } 
  ksort($arr); 
  return $arr; 
}

function tag_cloud() {

    $min_size = 10;
    $max_size = 30;

    $tags = tag_info();

    $minimum_count = min(array_values($tags));
    $maximum_count = max(array_values($tags));
    $spread = $maximum_count - $minimum_count;

    if($spread == 0) {
        $spread = 1;
    }

    $cloud_html = '';
    $cloud_tags = array(); // create an array to hold tag code
    foreach ($tags as $tag => $count) {
        $size = $min_size + ($count - $minimum_count) 
            * ($max_size - $min_size) / $spread;
        $cloud_tags[] = '<a . floor($size) . 'px' 
            . '"  target="_blank" href="http://www./index.php?s=' . $tag 
            . '" title="\'' . $tag  . '\' returned a count of ' . $count . '">' 
            . htmlspecialchars(stripslashes($tag)) . '</a>';
    }
    $cloud_html = join("\n", $cloud_tags) . "\n";
    return $cloud_html;
}
?>

2，css样式表
 

3，显示标签云的区域
 

php实现的dns解析类，如下：

<?php
/* -----------

   PHPresolver - PHP DNS resolver library
                 Version 1.1
   This library is free software; you can redistribute it and/or modify it
   under the terms of the GNU Lesser General Public License as published
   by the Free Software Foundation; either version 2.1 of the License, or any
   later version.

   This library is distributed in the hope that it will be useful, but
   WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
   or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU Lesser General Public
   License for more details.

   You should have received a copy of the GNU Lesser General Public License
   along with this library; if not,
   write to the Free Software Foundation, Inc.,
   59 Temple Place, Suite 330, Boston, MA 02111-1307  USA

  ----------------------------------------------
*/

 define( "DNS_RECORDTYPE_A", 1 );
 define( "DNS_RECORDTYPE_NS", 2 );
 define( "DNS_RECORDTYPE_CNAME", 5 );
 define( "DNS_RECORDTYPE_SOA", 6 );
 define( "DNS_RECORDTYPE_PTR", 12 );
 define( "DNS_RECORDTYPE_MX", 15 );

 define( "DNS_RECORDTYPE_AAAA", 28 );

 define( "DNS_RECORDTYPE_ANY", 255 );
 
 define( "DNS_RECORDTYPE_TXT", 16 );

/*
 list of record types not yet implemented

 define( "DNS_RECORDTYPE_A6", 38 );
 define( "DNS_RECORDTYPE_NULL", 10 );
 define( "DNS_RECORDTYPE_OPT", 41 );
 define( "DNS_RECORDTYPE_TKEY", 249 );
 define( "DNS_RECORDTYPE_TSIG", 250 );
 define( "DNS_RECORDTYPE_IXFR", 251 );
 define( "DNS_RECORDTYPE_AXFR", 252 );
 define( "DNS_RECORDTYPE_MAILB", 253 );
 define( "DNS_RECORDTYPE_MAILA", 254 );
 define( "DNS_RECORDTYPE_MD", 3 );
 define( "DNS_RECORDTYPE_MF", 4 );
 define( "DNS_RECORDTYPE_MB", 7 );
 define( "DNS_RECORDTYPE_MG", 8 );
 define( "DNS_RECORDTYPE_MR", 9 );
 define( "DNS_RECORDTYPE_WKS", 11 );
 define( "DNS_RECORDTYPE_HINFO", 13 );
 define( "DNS_RECORDTYPE_MINFO", 14 );
 define( "DNS_RECORDTYPE_RP", 17 );
 define( "DNS_RECORDTYPE_AFSDB", 18 );
 define( "DNS_RECORDTYPE_X25", 19 );
 define( "DNS_RECORDTYPE_ISDN", 20 );
 define( "DNS_RECORDTYPE_RT", 21 );
 define( "DNS_RECORDTYPE_NSAP", 22 );
 define( "DNS_RECORDTYPE_NSAP_PTR", 23 );
 define( "DNS_RECORDTYPE_SIG", 24 );
 define( "DNS_RECORDTYPE_KEY", 25 );
 define( "DNS_RECORDTYPE_PX", 26 );
 define( "DNS_RECORDTYPE_GPOS", 27 );
 define( "DNS_RECORDTYPE_LOC", 29 );
 define( "DNS_RECORDTYPE_NXT", 30 );
 define( "DNS_RECORDTYPE_EID", 31 );
 define( "DNS_RECORDTYPE_NIMLOC", 32 );
 define( "DNS_RECORDTYPE_SRV", 33 );
 define( "DNS_RECORDTYPE_ATMA", 34 );
 define( "DNS_RECORDTYPE_NAPTR", 35 );
 define( "DNS_RECORDTYPE_KX", 36 );
 define( "DNS_RECORDTYPE_CERT", 37 );
*/

 define( "DNS_OPCODE_QUERY" , 0x0000 );
 define( "DNS_OPCODE_IQUERY", 0x0800 );
 define( "DNS_OPCODE_STATUS", 0x1000 );
 define( "DNS_OPCODE_NOTIFY", 0x1800 );
 define( "DNS_OPCODE_UPDATE", 0x2000 );

 define( "DNS_RCODE_SUCCESSFUL"   , 0x0001 );
 define( "DNS_RCODE_MALFORMATED"  , 0x0002 );
 define( "DNS_RCODE_FAILEDSERVER" , 0x0003 );
 define( "DNS_RCODE_NAMEERROR"    , 0x0004 );
 define( "DNS_RCODE_UNIMPLEMENTED", 0x0005 );
 define( "DNS_RCODE_REFUSED"      , 0x0006 );

 define( "DNS_HEADERSPEC_IS_RESPONSE"         , 0x8000 );
 define( "DNS_HEADERSPEC_OPCODE_MASK"         , 0x7800 );
 define( "DNS_HEADERSPEC_AUTHORITIVE_ANSWER"  , 0x0400 );
 define( "DNS_HEADERSPEC_TRUNCATED"           , 0x0200 );
 define( "DNS_HEADERSPEC_RECURSION_DESIRED"   , 0x0100 );
 define( "DNS_HEADERSPEC_RECURSION_AVAILABLE" , 0x0080 );
 define( "DNS_HEADERSPEC_RESPONSE_SPEC_MASK"  , 0x0480 );
 define( "DNS_HEADERSPEC_QUERY_SPEC_MASK"     , 0x0300 );
 define( "DNS_HEADERSPEC_RESERVED"            , 0x0e00 );
 define( "DNS_HEADERSPEC_RESULT_CODE_MASK"    , 0x000f );

 define( "DNS_CLASS_INTERNET"                 , 0x0001 );

 define( "DNS_UDP_PACKET_MAX_LENGTH", 512 );

 class DNSRecord
 {
  var $type;
  var $name;
  var $dclass;
  var $ttl;
  var $specific_fields;

  function DNSRecord(
    $name,
    $type,
    $dclass = DNS_CLASS_INTERNET,
    $ttl = 0,
    $specific_fields = false ) {
   $this->name = $name;
   $this->type = $type;
   $this->dclass = $dclass;
   $this->ttl = $ttl;
   $this->specific_fields = $specific_fields;
  }
  function &getTypeSpecificField( $name ) {
   if( $this->specific_fields ) {
    return $this->specific_fields[$name];
   }
   return false;
  }
 }
 class DNSResolver
 {
  var $port;
  var $nameserver;
  var $timeout;
  function DNSResolver( $nameserver, $port = 53, $timeout = 1000000 ) {
   $this->port = $port;
   $this->nameserver = $nameserver;
   $this->timeout = $timeout;
  }
  function sendQuery( $dnsquery, $useTCP = false ) {
   $answer = false;
   $out_buf = $dnsquery->asOctets( false );
   $out_buf_len = strlen( $out_buf );
   if( $out_buf ) {
    if( $useTCP == false && $out_buf_len <= DNS_UDP_PACKET_MAX_LENGTH ) {
     /* connection by UDP */
     if( ( $sock = fsockopen( 'udp://'.$this->nameserver, $this->port, $this->timeout ) ) === false ) {
      return false;
     }
     socket_set_blocking( $sock, true );
     if( fwrite( $sock, $out_buf ) == $out_buf_len ) {
      $answer = new DNSAnswer( $sock, DNS_UDP_PACKET_MAX_LENGTH );
     }
     fclose( $sock );
    } else {
     /* connection by TCP */
     if( ( $sock = fsockopen( $this->nameserver, $this->port, $this->timeout ) ) === false ) {
      return false;
     }
     socket_set_blocking( $sock, true );
     if( fwrite( $sock, pack( 'n', $out_buf_len ) ) == 2 &&
         fwrite( $sock, $out_buf ) == $out_buf_len ) {
      $tmp = unpack( 'nl', fread( $sock, 2 ) );
      $limit_length = $tmp['l'];
      print $limit_length;
      $answer = new DNSAnswer( $sock, $limit_length );
     }
     fclose( $sock );
    }
   }
   return $answer;
  }
 }

 class DNSQuery 
 {
  var $id; // 1 - 65535
  var $header_opcode;
  var $query_record;
  var $flags;

  function DNSQuery( &$dnsrecord, $flags = DNS_HEADERSPEC_RECURSION_DESIRED )
  {
   $this->id = rand( 1, 255 ) | ( rand( 0, 255 ) << 8 );
   $this->flags = $flags & DNS_HEADERSPEC_QUERY_SPEC_MASK;
   $this->header_opcode = DNS_OPCODE_QUERY;
   $this->query_record = &$dnsrecord;
  }
  function asOctets() {
   if( $this->query_record->name === false ) { return false; }
   $buf = '';
   $buf .= pack( "nnnnnn", $this->id, DNS_OPCODE_QUERY | $this->flags, 1, 0, 0, 0 );
   $buf .= $this->query_record->name->asOctets();
   $buf .= pack( "nn", $this->query_record->type, $this->query_record->dclass );
   return $buf;
  }
 }

 class DNSMessageParser
 {
  var $stream;
  var $nbytes_read;
  var $octets;
  var $limit;

  function DNSMessageParser( $stream, $limit ) {
   $this->stream = $stream;
   $this->nbytes_read = 0;
   $this->octets = '';
   $this->limit = $limit;
  }
  function readStreamDirectly( $nbytes ) {
   if( ( $this->limit -= $nbytes ) < 0 ) {
    return false;
   }
   $buf = fread( $this->stream, $nbytes );
   $this->octets .= $buf;
   $this->nbytes_read += $nbytes;
   return $buf;
  }

  function readBufferedStream( $nbytes, $offset ) {
   if( $offset < $this->nbytes_read ) {
    $diff = $this->nbytes_read - $offset;
    if( $nbytes <= $diff ) {
     return substr( $this->octets, $offset, $nbytes );
    } else {
     $buf = substr( $this->octets, $offset, $diff );
     $nbytes -= $diff;
    }
   } else {
    $buf = '';
    while( $offset > $this->nbytes_read ) {
     if( $this->readStreamDirectly( $offset - $this->nbytes_read ) === false ) {
      return false;
     }
    }
   }
   if( ( $_buf = $this->readStreamDirectly( $nbytes ) ) === false ) {
    return false;
   }
   $buf .= $_buf;
   return $buf;
  }
  function getHeaderInfo() {
   if( ( $buf = $this->readStreamDirectly( 12 ) ) === false ) {
    $this = false;
    return;
   }
   return unpack( "nid/nspec/nqdcount/nancount/nnscount/narcount", $buf );
  }
  function getQueryRecords( $nrecs ) {
   $recs = array();
   while( --$nrecs >= 0 ) {
    if( ( $labels = $this->getLabels() ) === false ) {
     $this = false;
     return;
    }
    if( ( $buf = $this->readStreamDirectly( 4 ) ) === false ) {
     $this = false;
     return;
    }
    $info = unpack( "ntype/ndclass", $buf );

    $recs[] = new DNSRecord(
     new DNSName( $labels ),
     $info['type'],
     $info['dclass']
    );
   }
   return $recs;
  }
  function getResourceRecords( $nrecs ) {
   $recs = array();
   while( --$nrecs >= 0 ) {
    if( ( $labels = $this->getLabels() ) === false ) {
     return false;
    }
    if( ( $buf = $this->readStreamDirectly( 10 ) ) === false ) {
     return false;
    }
    $info = unpack( "ntype/ndclass/Nttl/nrdlength", $buf );
    switch( $info['type'] ) {
     case DNS_RECORDTYPE_CNAME:
     case DNS_RECORDTYPE_NS:
     case DNS_RECORDTYPE_PTR:
      if( ($_labels = $this->getLabels($info['rdlength']) ) === false ) {
       return false;
      }
      $specific_fields = array( 'dname' => new DNSName( $_labels ) );
      break;

     case DNS_RECORDTYPE_TXT:
      if( ($_labels = $this->getLabels($info['rdlength']) ) === false ) {
       return false;
      }
      $specific_fields = array( 'text' => $_labels );
      break;

     case DNS_RECORDTYPE_MX:
      if( ( $buf = $this->readStreamDirectly(2) ) === false ) {
       return false;
      }
      $specific_fields = unpack( 'npreference', $buf );
      if( ( $_labels = $this->getLabels($info['rdlength']-2) ) === false ) {
       return false;
      }
      $specific_fields['exchange'] = new DNSName( $_labels );
      break;

     case DNS_RECORDTYPE_A:
      if( ( $buf = $this->readStreamDirectly(4) ) === false ) {
       return false;
      }
      $specific_fields = array( 'address' => DNSName::newFromString( implode( '.', unpack( 'Ca/Cb/Cc/Cd', $buf ) ) ) );
      break;

     case DNS_RECORDTYPE_AAAA:
      if( ( $buf = $this->readStreamDirectly(16) ) === false ) {
       return false;
      }
      $specific_fields = array( 'address' => DNSName::newFromString( implode( '.', unpack( 
      'Ca/Cb/Cc/Cd/Ce/Cf/Cg/Ch/Ci/Cj/Ck/Cl/Cm/Cn/Co/Cp', $buf ) ).'.IP6.ARPA' ) );
      break;

     case DNS_RECORDTYPE_SOA:
      $specific_fields = array();
      if( ($_labels = $this->getLabels($info['rdlength']) ) === false ) {
       return false;
      }
      $specific_fields['source'] = new DNSName( $_labels );
      if( ($_labels = $this->getLabels($info['rdlength']) ) === false ) {
       return false;
      }
      $specific_fields['resp_person'] = array_shift( $_labels ).'@';
      $specific_fields['resp_person'] .= implode( '.', $_labels );

      if( ( $buf = $this->readStreamDirectly(20) ) === false ) {
       return false;
      }
      $specific_fields = array_merge(
       $specific_fields,
       unpack( 'Nserial/Nrefresh/Nretry/Nexpire/Nminttl', $buf )
      );
      break;

     default:
      if( $this->readStreamDirectly( $info['rdlength'] ) === false ) {
       return false;
      }
      $specific_fields = false;
    }

    $recs[] = new DNSRecord(
     new DNSName( $labels ),
     $info['type'],
     $info['dclass'],
     $info['ttl'],
     $specific_fields
    );
   }
   return $recs;
  }
  function getLabels( $max_length = 255, $offset = -1 ) {
   if( $offset < 0 ) { $offset = $this->nbytes_read; }
   $labels = array();
   for(;;) {
    if( --$max_length < 0 ) { return false; }
    if( ( $buf = $this->readBufferedStream( 1, $offset ) ) === false ) {
     return false;
    }
    $label_len = ord( $buf );
    ++$offset;
    if( $label_len < 64 ) {
     /* uncompressed */
     if( ( $max_length -= $label_len ) < 0 ) { return false; }
     if( ( $labels[] = $this->readBufferedStream( $label_len, $offset ) ) === false ) {
      return false;
     }
     $offset += $label_len;
     if( $label_len == 0 ) { break; }
    } else {
     /* compressed */
     if( ( $buf = $this->readBufferedStream( 1, $offset ) ) === false ) {
      return false;
     }
     if( --$max_length < 0 ) {
      return false;
     }
     $_offset = ( ( $label_len & 0x3f ) << 8 ) + ord( $buf );

     if( ($_labels = $this->getLabels( $offset - $_offset, $_offset )) === false ) {
      return false;
     }
     $labels = array_merge( $labels, $_labels );
     break;
    }
   }
   return $labels;
  }
 }

 class DNSAnswer
 {
  var $id;
  var $result_code;
  var $flags;
  var $rec_query;
  var $rec_answer;
  var $rec_authority;
  var $rec_additional;

  function DNSAnswer( &$stream, $limit ) {
   $msgparser = new DNSMessageParser( $stream, $limit );

   $info = & $msgparser->getHeaderInfo();

   $this->id = $info['id'];
   $this->result_code = $info['spec'] & DNS_HEADERSPEC_RESULT_CODE_MASK;
   $this->flags = $info['spec'] & DNS_HEADERSPEC_RESPONSE_SPEC_MASK;

   $nrec_query = $info['qdcount'];
   $nrec_answer = $info['ancount'];
   $nrec_authority = $info['nscount'];
   $nrec_additional = $info['arcount'];
   if( ( $this->rec_query = &$msgparser->getQueryRecords( $nrec_query ) ) === false ) {
    $this = false;
    return;
   }

   if( ( $this->rec_answer = &$msgparser->getResourceRecords( $nrec_answer ) ) === false ) {
    $this = false;
    return;
   }
   if( ( $this->rec_authority = &$msgparser->getResourceRecords( $nrec_authority ) ) === false ) {
    $this = false;
    return;
   }

   if( ( $this->rec_additional = &$msgparser->getResourceRecords( $nrec_additional ) ) === false ) {
    $this = false;
    return;
   }
  }
 }
 class DNSName
 {
  var $labels;

  function DNSName( $labels ) {
   $this->labels = & $labels;
  }
  function isRealDomainName() {
   $i = count( $this->labels ) - 1;
   if( $i >= 1 && strtoupper($this->labels[$i-1]) == 'ARPA' ) {
    return false;
   }
   return true;
  }
  function newFromString( $domain_name ) {
   if( strpos( $domain_name, ':' ) !== false && !ereg( '[^0-9a-fA-f:.]', $domain_name ) ) {
    /* IPv6 address literal expression spec */
    $labels = array();
    $components = explode( ':', $domain_name );
    $ncomponents = count($components);
    $offset = $ncomponents;
    while( --$offset >= 0 ) {
     $subcomps = explode( '.', $components[$offset] );
     $nsubcomps = count( $subcomps );
     if( $nsubcomps == 1 ) {
      if( $subcomps[0] == '' ) {
       $_offset = 0;
       while( $components[$_offset] != '' ) {
        ++$_offset;
       }
       $count = 9-($ncomponents-$offset)+$_offset;
       while( --$count >= 0 ) {
        $labels[] = '0';
        $labels[] = '0';
        $labels[] = '0';
        $labels[] = '0';
       }
       if( $_offset < $offset ) {
        $offset = $_offset;
       }
      } else {
       $compval = hexdec( $subcomps[0] );
       $labels[] = dechex( $compval & 0x0f );
       $compval >>= 4;
       $labels[] = dechex( $compval & 0x0f );
       $compval >>= 4;
       $labels[] = dechex( $compval & 0x0f );
       $compval >>= 4;
       $labels[] = dechex( $compval & 0x0f );
       $compval >>= 4;
      }
     } elseif( $nsubcomps == 4 ) {
      $labels[] = dechex( $subcomps[3] );
      $labels[] = dechex( $subcomps[2] );
      $labels[] = dechex( $subcomps[1] );
      $labels[] = dechex( $subcomps[0] );
     } else {
      return false;
     }
    }
    $labels[] = 'IP6';
    $labels[] = 'ARPA';
    $labels[] = '';
   } else {
    if( substr( $domain_name, -1, 1 ) != '.' ) {
     $domain_name .= '.';
    }
    $labels = explode( '.', $domain_name );
    $nlabels = count( $labels );
    if( $nlabels == 5 && !ereg( '[^0-9.]', $domain_name ) ) {
     /* IPv4 raw address literal representation spec */
     $tmp = (string)$labels[0];
     $labels[0] = (string)$labels[3];
     $labels[3] = $tmp;
     $tmp = (string)$labels[1];
     $labels[1] = (string)$labels[2];
     $labels[2] = $tmp;
     $labels[4] = 'IN-ADDR';
     $labels[5] = 'ARPA';
     $labels[6] = '';
    }
   }
   return new DNSName( $labels );
  }
  function asOctets() {
   $upto = count( $this->labels );
   $buf = '';
   for( $offset = 0; $offset < $upto; ++$offset ) {
    $label_len = strlen( $this->labels[$offset] );
    $buf .= pack( "C", $label_len ).$this->labels[$offset];
   }
   return $buf;
  }
  function getCanonicalName() {
   return implode( ".", $this->labels );
  }
 }
?>