Setting outgoing calls constraints in Kerio Operator

You may want to limit some or all outgoing calls for a variety of reasons. For example, should an outside party obtain the username and password of one of your employees, they could use your PBXPrivate Branch Exchange - System that connects telephone extensions and switches calls. for international calls—possibly involving fraud and costing you money. It is therefore critical to have calls to external networks well configured.

You can set outgoing call constraints to prevent these types of attacks.

Restricting the length of individual outgoing calls

To set the maximum call duration:

  1. In the administration interface, go to Configuration > Security.
  2. Set Maximum duration of each outgoing call. The recommended value is 2 hours.

Restricting the number and length of outgoing calls

You can limit all outgoing calls by creating special rules in the section Configuration > Security in table Outgoing calls constraints.

The default rule limits the number of outgoing calls to 50 per hour and total call duration to 2 hours per day.


A manufacturer in the United States sells and primarily has contacts just in the U.S. and Canada, but has a factory in Mexico. Management wants to limit calls to other countries.

  1. In the administration interface, open Configuration > Security and click Add.
  2. Type a rule name, such as Constraints for Mexico).
  3. In the Apply to these outgoing calls section, select All except listed and click Add.
  4. Add the calling prefixes as a single string:
  • For local calls: 9 (outside line)
  • For U.S. and Canada: 91 (outside line + 1 preceding the area code)
  • For Mexico: 901152 (outside line + 011 for international call + 52 for Mexico's country code)
  1. Define the conditions: Set Maximum calls count to 10 per hour and Maximum total calls duration to 1 hour a day.
  2. When the conditions are met, Kerio Operator can send a warning email or block all outgoing calls.

We recommend creating:

  • One soft rule with lower limits that sends warning messages via email.
  • Another rule with higher limits that blocks the PBX.


If the limits are reached and the PBX is blocked, no one will be able to make calls to the restricted prefixes. However, an administrator can unlock the PBX in section Configuration > Security. We recommend making a thorough analysis of your calls before setting restrictions so that the PBX is not blocked by standard operations.

In addition to these settings, you can also configure similar rules for specific users or groups of users. For more information refer to Disabling outgoing calls to certain countries or regions.