PROBLEM
I need to block spammers using forged From: headers.

ENVIRONMENT

• On-Premise Server + WebMail Installations: Version 6.0 > Current Version

CAUSE
Some spammers may wish to use your server as a relay, using SMTP Authentication with forged From: headers.

RESOLUTION

You can block them by doing the following steps:

1. Open the configure file in your editor
   

   /usr/local/atmail/mailserver/configure

2. Find this line:
   

   accept authenticated = *

3. ABOVE that line, add the following:
   

   deny condition = ${if match{$sender_address}{$authenticated_id}{0}{1}}
   log_message = Email blocked - Possible Spam 

4. Save the changes to the configure file, and restart Exim
   

   killall -HUP exim