Which action is correct with respect to toll fraud prevention configuration in the Cisco Unified Communications Manager Express?

Question

Options

• AConfigure Direct Inward Dial for Incoming ISDN Calls with overlap dialing.
• BConfigure IP Address Trusted Authentication for Incoming VoIP Calls.
• CConfigure the command no ip address trusted authenticate under "voice service voip".
• DEnable Secondary Dial tone on Analog and Digital FXO Ports.

• A
  16% (6)
• B
  73% (27)
• C
  8% (3)
• D
  3% (1)

Explanation

Option B is correct because enabling IP Address Trusted Authentication under voice service voip restricts incoming VoIP calls to only those originating from explicitly trusted IP addresses - preventing unauthorized external sources from injecting calls through your CUCME system to make fraudulent long-distance or international calls at your expense.

Why the distractors are wrong:

• A - Direct Inward Dial with overlap dialing is a call delivery method for ISDN, not a security control; it does nothing to prevent toll fraud.
• C - This is a trap: no ip address trusted authenticate disables the trusted authentication feature, making the system more vulnerable to toll fraud, not less.
• D - Secondary dial tone on FXO ports signals that a PSTN line is seized, but it does not authenticate or restrict who can use that path.

Memory tip: Think of the "no" in option C as a red flag - on a security question, "no" before a security command almost always means you're removing protection. "Trusted Authentication ON = toll fraud locked OUT."

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