How to avoid fake CallerIDs?

To avoid calls from fake CallerIDs you can override CallerID which is set on users SIP phone by setting it on his device settings. Since only administrator can change this value it is unable to use a fake CallerID.

To do it go to SETTINGS block -> Users -> Devices. Click the Edit icon and you will see this window:

Fill in the fields with required information and click Update at the bottom of the window.