Which two recommendations are made to optimize Cisco UCM configuration to reduce the number of toll fraud incidents in an organization? (Choose two.)

To mitigate toll fraud, two primary Cisco UCM configurations are recommended. First, properly classify all route patterns as either "on-net" (internal) or "off-net" (external/PSTN). Then, enable the "Block OffNet to OffNet Transfer" service parameter. This prevents an external caller from transferring a call to another external number, a common toll fraud technique known as "tromboning." Second, the Calling Search Space (CSS) assigned to inbound PSTN gateways must be restricted. This inbound CSS should only contain partitions with internal destinations (e.g., IP phones, auto attendants), explicitly excluding partitions that contain route patterns leading back out to the PSTN. This prevents external callers from directly dialing an external number through the gateway.

A. Classifying all route patterns as on-net is an incorrect configuration that would disrupt proper call routing logic for external calls.
C. Classifying all route patterns as off-net is an incorrect configuration that would miscategorize internal extension-to-extension calls.
D. Allowing an inbound gateway's CSS to access PSTN destinations is a major security vulnerability that directly enables toll fraud.

1. Cisco Unified Communications Manager Security Guide, Release 12.5(1)SU1, "Toll Fraud Prevention" chapter, "Call Transfers" section.

This section states, "To prevent toll fraud that is related to call transfers, you can block a transfer operation when both parties are external. To do this, you must classify all your route patterns as either on-net or off-net and set the 'Block Off-Hook to Off-Hook Transfer' service parameter to True." This directly supports option B.

2. Cisco Unified Communications Manager Security Guide, Release 12.5(1)SU1, "Toll Fraud Prevention" chapter, "Calling Search Spaces and Partitions" section.

This section states, "For inbound calls from the PSTN or other untrusted networks, the calling search space that is assigned to the gateway must be restricted to accessing only internal destinations." This directly supports option E and refutes option D.

3. Cisco Collaboration System 12.x Solution Reference Network Designs (SRND), "Security" chapter, "Toll Fraud" section.

Under the "Recommendations for Preventing Toll Fraud" subsection, it advises: "Restrict the inbound PSTN gateway's calling search space (CSS) to a partition that contains only internal extensions and not the PSTN access route patterns." This provides further support for option E.