Extension Wikipage: https://www.mediawiki.org/wiki/Extension:BounceHandler
The BounceHandler extension generates a unique VERP address on every sent email, and has the bouncehandler API that can handle incoming email bounces once the bounce is HTTP POSTed to it via curl from exim. The extension was built as part of the VERP project to properly handle email bounces.
Pipe incoming bounces to the bouncehandler API:-
You need to add the following to your incoming mails to *@wikimedia.com receving PIPE transport:
command = /usr/bin/curl "action=bouncehandler" --data-urlencode "email@-" http://$IP/api.php
The genrated VERP address is of the form
$wikiId-base36( $UserID )-base36( $Timestamp )-hash( $algorithm,$key, $prefix )@$email_domain
$wikiId - The wiki database name, to support multiple wikis
$userID - The user_id from table 'user' - to uniquely identify a recipient.
$Timestamp - The unix timestamp.
$prefix = $wikiId. '-'. base_convert( $uid, 10, 36). '-'. base_convert( $timeNow, 10, 36);