Policyd have module quotas. This module can use for limit sending/receipt email. As example just allow sending/receipt email 200 emails/hours/users. If your email server attacked by spam or compromised password some users and used by spammer, the maximum email can be sent as many as 200 emails per hour. This policy will safe your IP public from blacklist on RBL. Besides, you can check who user send email with many email
How To Install Policyd on Zimbra
This guidance is step by step how to install policyd on Zimbra 8.5 and latest
su - zimbra zmprov ms `zmhostname` +zimbraServiceInstalled cbpolicyd +zimbraServiceEnabled cbpolicyd
Activate Policyd WebUI
– For Zimbra 8.5/8.6
Run the following command as root
cd /opt/zimbra/httpd/htdocs/ ln -s ../../cbpolicyd/share/webui .
Edit file /opt/zimbra/cbpolicyd/share/webui/includes/config.php and putting “#” on front of all the lines beginning with $DB_DSN and adding the following line just before the line beginning with $DB_USER.
