install and configure policyd on zimbra

Ahmad Imanudin has a nice series of tutorials on installing and configuring policyd on Zimbra.

1. Install and enable web ui.

How To Install PolicyD on Zimbra 8.5

2. Password protect web ui with .htaccess

Zimbra Tips: How To Protect Policyd WebUI

3. Configure policyd using web ui

Zimbra Tips : How To Configure Rate Limit Sending Message on PolicyD

4. Reject unlisted domain using policyd web ui

https://imanudin.net/2014/09/11/improving-anti-spam-reject-unlisted-domain-on-zimbra-8-5/