CBPolicyd with Zimbra MySQL

 - This article is a Work in Progress, and may be unfinished or missing sections.

Setting up CBPolicyd with Zimbra MySQL

Execute the following steps on MTA Node to setup CBPolicyd with Zimbra MySQL

• Clone the repo:

$ git clone https://github.com/Zimbra/zm-core-utils.git

• Go to zm-core-utils/src/bin/ directory and execute the cbpolicyd.sh script:

$ bash cbpolicyd.sh

• If you want to change or review your polices using mysql client, as ad-policyd_db user login to mysql database and execute the command.

$ /opt/zimbra/bin/mysql policyd_db -u ad-policyd_db -p 

ad-policyd_db user password can be obtained using below command:

$ grep Pass /opt/zimbra/conf/cbpolicyd.conf.in

SELECT * FROM quotas_limits;

• Following will be the output:

+----+----------+-----------------------+--------------+---------+----------+
| ID | QuotasID | Type                  | CounterLimit | Comment | Disabled | 
+----+----------+-----------------------+--------------+---------+----------+
|  1 |        1 | MessageCount          |           10 | NULL    |        0 |
|  2 |        1 | MessageCumulativeSize |         8000 | NULL    |        0 |
|  3 |        2 | MessageCount          |           12 | NULL    |        0 |
|  4 |        3 | MessageCount          |          100 | NULL    |        0 |
|  5 |        4 | MessageCount          |          125 | NULL    |        0 |
+----+----------+-----------------------+--------------+---------+----------+

• CBPolicyd has been installed successfully. Following are the details of the policy:
  • Rate limit any sender from sending more than 100 emails every 60 seconds. Messages beyond this limit are deferred.
  • Rate limit any @domain from receiving more than 125 emails in a 60 second period. Messages beyond this rate are rejected.

• For testing purpose, we can set the following policy:
  • 2 emails every 60 seconds. Messages beyond this limit are deferred.
  • 2 emails in a 60 second period. Messages beyond this rate are rejected.

• As ad-policyd_db user, login to the MySQL database and execute the following commands for updating quotas_limits table to set the above mentioned policies:

$ /opt/zimbra/bin/mysql policyd_db
UPDATE quotas_limits SET CounterLimit = 2 WHERE ID = 4;
UPDATE quotas_limits SET CounterLimit = 2 WHERE ID = 5;

• To make the configuration effective, execute these commands as zimbra user:

$ su - zimbra
$ zmprov ms `zmhostname` +zimbraServiceEnabled cbpolicyd
$ zmprov ms `zmhostname` zimbraCBPolicydQuotasEnabled TRUE 

• Restart services:

$ zmmtactl restart
$ zmcbpolicydctl start

Note:
The installed policy is a basic template to get started.
In many cases you will want to set the `Period` column in `quotas` table to 600 or 3600 and set `CounterLimit` to around 100 for all records of type `MessageCount` in `quotas_limits` table.
It is recommended to monitor the users e-mailing behavior prior to installing cbpolicyd. Be prepared to alter the limits after installing in case your users send more email then expected.

Tested versions:
Centos 7: 9.0.0_P14
Centos 8: 8.8.15_P21
Ubuntu 16: 9.0.0_P14
Ubuntu 18: 8.8.15_P21

Testing the CBPolicyd configuration

• Login to Zimbra Modern Web App.
• Send 2 emails within 60 seconds.
• You will see an error message in UI:

You are sending too many emails, contact helpdesk.

• Similar message will also get logged in /var/log/zimbra.log and /opt/zimbra/log/cbpolicyd.log