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| Prev-Msg | Prev-Thread | Postfix-users | May-2008 | Next-Thread | Next-Msg |
| Subject: | my solution to fight backscatter email |
| Group: | Postfix-users |
| From: | nik600 |
| Date: | 8 May 2008 |
i want to show you my solution about how to fight backscatter, pleas
tell me what do you think about that:
The concept is to store in a whitelist-db To and CC emails of my
outbound emails, and when i receive an email with a delivery error,
check if the Final-Recipient is in my whitelist.
I've implemented it in 2 php files, one must be run for each outgoing
email, and the other one for each incoming email.
/*
************************ FOR EACH OUTGOING EMAIL
*/
<?php
/*
the content of the email can be retrieved or by stdin or by reading
it from a tmpfile
*/
$content = file_get_contents("Sent");
/*
look only in the headers of the email
*/
$headers = strtoupper(substr($content,0,strpos($content,"Content-Type:")));
/*
retrieve To: and CC: destinations
*/
$start_to = strpos($headers,"\nTO:");
$start_cc = strpos($headers,"\nCC:");
$start_subject = strpos($headers,"\nSUBJECT:");
if($start_cc!==false){
$to = substr($headers,$start_to,$start_cc-$start_to);
$cc = substr($headers,$start_cc,$start_subject-$start_cc);
}else{
$to = substr($headers,$start_to,$start_subject-$start_to);
}
$res_to = get_address($to);
$res_cc = get_address($cc);
$final_email = array_merge($res_to,$res_cc);
foreach($final_email as $email){
/*
store email in my backscatter whitelist
*/
}
/**
* return an array filled with the emails found in $address
*/
function get_address($address){
$results = array();
$address = explode(",",$address);
foreach($address as $email){
if(strpos($email,"<")!==false){
$mail = substr($email,strpos($email,"<")+1,strpos($email,">")-strpos($email,"<" )-1);
}else{
$mail=$email;
}
$mail = trim($mail);
array_push($results,$mail);
}
return $results;
}
?>
/*
************************ FOR EACH INCOMING EMAIL
*/
<?php
$content = file_get_contents("backscatter");
$final_recipient = strpos($content,"Final-Recipient: rfc822;");
if($final_recipient!==false){
/*
this is a mail with a delivery failure
i try to retrieve the original destination of the email
*/
$email_final_recipient =
substr($content,$final_recipient,strpos($content,"\n",$final_recipient)-$final_r ecipient);
$email_final_recipient =
substr($email_final_recipient,strlen("Final-Recipient: rfc822;"));
$email_final_recipient = trim($email_final_recipient);
$email_final_recipient = strtoupper($email_final_recipient);
/*
now i check if the email is in my backscatter whitelist
*/
check....
}else{
/* OK, this email isn't a mail with a delivery failure */
}
?>
--
/*************/
nik600
https://sourceforge.net/projects/ccmanager
https://sourceforge.net/projects/reportmaker
https://sourceforge.net/projects/nikstresser
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