Processing method of high spam rate in HTML format

Original e-Mail used content-type:text/html

The following is the X-spam score, when the score more than 6 points are treated as junk mail

X-spam-status:yes, score=6.3 required=6.0 tests=content_type_present,Directunknown, Html_message,mime_html_only,only1hopdirect,rdns_none,TO_NO_BRKTS_FROM_MSSP, To_no_brkts_nordns_html,uribl_blocked,utf8 autolearn=No version=3.3.1X-spam-report: *0.0uribl_blocked ADMINISTRATOR notice:the query to URIBL was BLOCKED.    * See Http://wiki.apache.org/spamassassin/DnsBlocklists#dnsbl-block * For more information. *      [URIs:handbook.jp]    * -0.1content_type_present Exists:content-type *0.3Directunknown directly received spam from suspicious dynamic IP *1.0Only1hopdirect Only1hopdirect *1.0html_message body:html included in MESSAGE *0.4mime_html_only body:message only have text/html MIME parts *-0.1 UTF8 Raw:utf-8Message body *1.3Rdns_none delivered to internal network by a host with no RDNS *2.5TO_NO_BRKTS_FROM_MSSP Multiple formatting errors *0.0 to_no_brkts_nordns_html to:misformatted and NO RDNS and HTML only

The solution is to use content-type:multipart/alternative

This type can send two types of mail text/plain and text/html at the same time, greatly reducing the score of the message

The following is a multipart/alternative of this type of score because it is less than 6 points without x-spam-report

X-spam-status:no, score=3.5 required=6.0 tests=content_type_present,    directunknown, HTML_MESSAGE, Multipart_alternative,only1hopdirect,rdns_none,    uribl_blocked, UTF8 autolearn=no version=3.3.1

Here is the specific code

functionSendalternativemail ($to,$from,$subject,$plainmessage,$htmlmessage,$BCC=NULL,$CC=NULL) {    $to= Base64 ($to); $from= Base64 ($from); $subject= ' =? UTF-8? B? '.Base64_encode($subject) . '? = '; $boundary=uniqid(' NP ');
Set Header$headers= "mime-version:1.0\r\n"; $headers. = "From:".$from." \ r \ n "; $CC&&$headers. = "Cc:$CC\ n "; $BCC&&$headers. = "BCC:$BCC\ n "; $headers. = "Content-type:multipart/alternative;boundary=".$boundary. "\ r \ n"; Set Plain Body$message= "\r\n\r\n--".$boundary. "\ r \ n"; $message. = "content-type:text/plain;charset=utf-8\r\n\r\n"; $message.=$plainmessage; Set HTML body$message. = "\r\n\r\n--".$boundary. "\ r \ n"; $message. = "content-type:text/html;charset=utf-8\r\n\r\n"; $message.=$htmlmessage; End$message. = "\r\n\r\n--".$boundary. "--"; return Mail($to,$subject,$message,$headers);}
encode email address functionBase64 ($string){    if(!$string) {        return NULL; }    $array=Explode(‘,‘,$string); foreach($array  as&$a) {        $a=Trim($a); if(Preg_match('/(. *) (<[^>][email protected][^>]+>) $/u ',$a,$match)) {            $a= ' =? UTF-8? B? '.Base64_encode($match[1]). '? = '.$match[2]; }    }    return implode(‘,‘,$array);}

Reference: http://krijnhoetmer.nl/stuff/php/html-plain-text-mail/

Processing method of high spam rate in HTML format