# Add an Outbound Call Frequency Restriction Rule

Outbound Call Frequency Restriction rules put a ceiling on how many outbound calls can be placed inside a defined time window. Capping call volume this way is one of your best defenses against toll fraud: if credentials are compromised, an attacker can only dial out so many times before the system blocks further calls.

:::note
Toll fraud is the abuse of a phone system to place unauthorized outbound calls, usually with stolen extension credentials and usually to premium-rate or international numbers. Because those calls are billed to your account, a single breach can generate large charges very quickly. A frequency limit caps the damage even if an account is compromised.
:::

Cloud Voice ships with a built-in rule that allows an extension a maximum of 5 outbound calls per second. You can leave that default in place and add rules of your own to match how your organization actually places calls.

## Create a rule

1. Sign in to the management portal and go to **Security > Security Rules > Outbound Call Frequency Restriction**, then click **Add**.
2. In the dialog that opens, fill in the rule:
   1. In the **Name** field, enter a label that will help you recognize the rule later.

      :::tip
      Give the rule a descriptive name that reflects what it does, for example the call count and window (such as "Max 10 calls per minute"). Clear names save time once you have several rules to choose from.
      :::
   2. Click **Add**, then define the limit:
      - **Number of Calls**: The maximum number of outbound calls allowed.
      - **Time Period**: The length of the window the limit applies to. Enter a value and choose **Minute(s)** or **Second(s)** as the unit.

      :::caution
      Set the limit high enough to cover normal business calling. If the cap is too low for the time window, the system will start blocking legitimate outbound calls once an extension reaches it, which users experience as calls that will not connect. Base the number on how your busiest users actually dial.
      :::
   3. Click **Save**, then **Apply**.

      :::note
      Changes do not take effect until you click **Apply**: saving alone stores the rule but does not activate it.
      :::

## Next step

Creating the rule does not enforce it on its own. To put it into effect, assign it to the extensions you want to protect.

:::caution
A rule has no effect while it sits unassigned. Until you apply it to one or more extensions, those extensions are still governed only by the default limit. See [Limit Outbound Call Frequency of an Extension](/pbx/administrator-guide/limit-outbound-call-frequency-of-an-extension/) to complete the setup.
:::