please help , this month we already receive a lot of email from someone we don't know which the email contain an attachment (ransomware).
as i know , they send email "TO" someone not exist in my user zimbra account .
for example this original email :
\Content-Type: multipart/mixed; boundary="===============1249967981=="
Subject: Request for Quotation of Screw Decanter Centrifuge_CE1
Project/AA167194000000 (Muhan Technical)
To: Odsuren Batgerel <email@example.com>
From: "Odsuren Batgerel" <firstname.lastname@example.org>
Date: Mon, 11 May 2020 19:32:34 -0700
the email from them self to them self, but it's coming to my inbox (which not our mail domain).
is there anyway to block email like above to incoming to my zimbra users inbox ?