Hello to you all!
I just started working on a new company, and they installed Zimbra Collaboration Suite a couple of months ago.
I've been getting this last 2 days more than 3000 emails deferred from random email accounts of our domain coming from different ip addresses (i've blocked most of ip addresses on salocal.cf.in but i keep getting too many deferred emails)
All of our users have installed Thunderbird with SSL-TLS with authentication for incoming & outgoing emails, and they all changed their passwords last week.
This is our current Zimbra version: Release 7.1.0_GA_3140.UBUNTU8 UBUNTU8 FOSS edition.
As i started checking /var/log/zimbra.log i kept getting this lines:
Jun 6 06:50:36 mail amavis: (30206-14) [B]Open relay? Nonlocal recips but not originating
I also tried different open relay testing sites and i kept failing all test (Message received: Relays accepted by remote host)
Is there any way to disable open relay on Zimbra? if so... how do i do it? i read many threads without any solution.
Kind regards in advance for all your help and assistance