How can I prevent exim4 from accepting messages from an empty sender?

Question

Exim

In the logs I saw:

2017-02-17 09:53:09 1bla-blabgbbla <= <> R=1bla-blablabla U=Debian-exim P=local S=84741
2017-02-17 09:53:09 1bla-blablabla => user <[email protected]> R=dovecot_user T=dovecot_delivery

Actually strains the sender <>. How can I stop receiving such emails?

Answer 1

Don't ban it, it will end badly. Technical messages are coming from this sender. For example, about the impossibility of delivering letters from your users to some external addresses.