CUCM 8.x – Block Inbound Calls by ANI (Calling Number)

If you are using to SIP or H.323 gateways, it is quite simple to block inbound or outbound calls at the gateway based on ANI (Calling Number) or DNIS (Called Number); the dial peer configuration can match based on either. However, many CUCM deployments run MGCP gateways because they are easier to manage when the voice guys are not network guys. Prior to CUCM 8.x, you could only block calls based on the DNIS if you used MGCP gateways. There is a feature in CUCM 8.x and higher that allows you to block calls based on ANI *or* DNIS, even if you are using MGCP gateways: Route Next Hop by Calling Party.

“Route Next Hop by Calling Party” is an option that can be applied to Translation Patterns in CUCM 8.x and higher. In order to block calls based on ANI, you will need to add 2 partitions and 2 calling search spaces:

• Partitions – InboundCalls_PT, FilterList_PT
• Gateway_CSS – contains InboundCalls_PT
• FilterList_CSS – contains FilterList_PT

You will also need to add several translation patterns:

• “!” – InboundCalls_PT – Route Next Hop by Calling Party – CSS: FilterList_CSS – use ANI to match the next step using the FilterList_CSS
• “!” – FilterList_PT – CSS: Internal_CSS – this matches all calls without a more specific match
• “” (blank) – FilterList_PT – CSS: Internal_CSS – this matches all calls without an ANI, i.e. if caller ID is blocked or unavailable

The Gateway_CSS is assigned to your inbound connection (SIP trunk, PRI, FXO, etc.) and the FilterList_CSS is used by translation patterns to route calls through the list of blocked patterns. At this point your call flow will look something like this:

Gateway_CSS
  InboundCalls_PT
    Translation Pattern
      “!” – route all calls
      Route next hop by calling party
      CSS: FilterList_CSS

FilterList_CSS
  FilterList_PT
    Translation Pattern
      “!” – route all calls not specifically blocked
      CSS: Internal_CSS
    Translation Pattern
      "" (blank) - route all calls without Caller ID
      CSS: Internal_CSS

In order to block numbers, simply add translation patterns to the FilterList_PT that match the ANI (Calling Number) and choose “Block this pattern”.

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Tags: cisco, cucm, voice

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