I have a fresh exim4
install without any tweaks on a Debian 8.6
machine.
I use it to send emails from PHP:
; /etc/php5/fpm/conf.d/mail.ini
[mail function]
sendmail_path = /usr/sbin/exim4 -t
mail.add_x_header = On
mail.log = syslog
Recently we began to receive a lot of spam emails, which exim tries to send back, because of inexistent recepients.
So, I ran exim statistics tool and got:
# /usr/sbin/eximstats -ne -byhost -bydomain -byemail /var/log/exim4/mainlog
Top 50 local senders by message count
-------------------------------------
Messages Bytes Average Local sender
603 1395KB 2368 Debian-exim
38 127KB 3422 website1user
33 94KB 2916 website2user
7 91KB 13KB website3user
Normal sites send tens of emails per day, and Debian-exim
user sends hundreds of ones to some random addresses, which I even don’t know.
How can I completely deny some specified users to send emails through exim4
?
Should I deny Debian-exim
user? What is it used for?
Notice that I mean not sender email addresses to deny (they can be replaced with no effort in headers of the email) but local users here.
(Maybe I have completely lost an understanding of situation?)
Thank you.