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UCM Security Manual
Allow Guest Calls
“Allow Guest Calls” option can be found on web GUI
PBX Settings
SIP Settings
General page.
We
highly recommend
NOT
to turn on this option for any deployments. Enabling “Allow Guest Calls” will stop
the PBX from authenticating incoming calls from unknown or anonymous callers. In that case, hackers get
the chance to send INVITE to UCM and the UCM will place the call without authentication. This can result
in high toll charges.
The administrator might also want to check CDR regularly to make sure there is no
suspicious calls in the early stage of deployment.