Configure Expressway to Block External Callers from Reaching a Specific Internal Address

C.

To ensure that an external caller cannot reach a specific internal address, an administrator can use the call policy rules feature in the Expressway-E. Call policy rules are used to define what actions should be taken when certain criteria are met, such as when a call is made to a specific destination or from a specific source.

The steps to configure a call policy rule to block calls to a specific internal address on the Expressway-E are as follows:

1. Log in to the Expressway-E web interface.
2. Click on the "Configuration" tab.
3. Click on "Call Policy" in the left-hand menu.
4. Click on the "New Rule" button to create a new call policy rule.
5. In the "Rule Name" field, enter a descriptive name for the rule (e.g. "Block Calls to Internal Address").
6. In the "Match Criteria" section, select the "Called Number" option.
7. In the "Pattern" field, enter the specific internal address you want to block (e.g. "5551234").
8. In the "Action" section, select the "Reject" option.
9. Click on the "Save" button to save the new call policy rule.

Once the call policy rule has been created and saved, any external calls made to the specific internal address will be rejected by the Expressway-E.

Option B, adding the specific URI in the firewall section of the Expressway and blocking it, is not the recommended solution as the firewall section is intended for managing the traversal zone policies and network address translation (NAT) rules.

Option C, configuring Forced Authorization Codes (FAC) for the destination alias on the Expressway, is not the appropriate solution as FAC is a call restriction feature that requires users to enter a code to make a call, and it cannot block a specific address.

Option D, adding a search rule to route all calls to the Cisco Unified Communications Manager (UCM), is not relevant to blocking a specific internal address as it is only used to route calls to a specific destination.