The Acme Jet Boats Company is installing an IP videoconferencing system in the corporate office. Users need the ability to dial out to external H.320 videoconferences. The company is installing a videoconferencing gateway, but is concerned that outside callers may be able to dial the gateway and then hairpin back out to the PSTN. What does Cisco recommend to ensure that this cannot happen?
A.
Set up the gatekeeper to allow only outgoing calls that originate internally.
B.
Configure the Cisco CallManager so that the gateway terminates hairpinned calls.
C.
Configure the gateway to allow only outgoing calls that originate internally.
D.
Use the “#” digit in the service prefix so that hairpinned call attempts will fail.