IVR/DISA - allow direct call to a known extension and nothing else


I would like to use a single DID and allow an external caller to reach one of the many internal extensions (like if they all had a dedicated DID).
I want to limit the possibilities of this call to go anywhere but ring the extension specified by the caller when the call enters.

Is IVR the right way ?
Enable Direct Dial ON or one IVR entry for each extension “allowed” to receive a direct call.

Is it risky ?


Yeah, IVR is the best way for this. You can turn Direct Dial on and setup no IVR options or you could include a single IVR option like 0 for an operator/receptionist if you want.

That said, there IS a way to filter what Extensions can be direct dialed. Create a Directory in Applications > Directory and add all the numbers you want to be accessible. If you only want to remove a few from the complete list of Extensions, use the All Users option to populate the list with everyone to start. You can also add custom dial entries to the Directory (uses the from-internal context, so be careful what you add!).

Custom entries are handy for specifying things like Queues and Ring Groups, then these can be direct dialed from the IVR too…but you might just want to add them as standard IVR entries so you can “alias” them with a different number. Example: You have a 200 Sales RG and Ext 201, 202, 203 in it. When customers call in, you want to ring the RG when they try to direct dial ANY of the Exts in it. Create IVR options 200, 201, 202, 203 and point all to the RG, then ensure those numbers are not in the Directory you are using for Direct Dial.

If you just want EVERY Extension included (but not Ring Groups, etc), then the standard Enabled selection on IVR Direct Dial is suitable. If you have no Directories created, the IVR Direct Dial option will only show Disabled and Enabled.

So, by leveraging Directory and IVR, you have a lot of control over how customers reach the inside directly.

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Oh, and from a security and risk perspective: So long as you aren’t adding custom entries to the Directory that are actually Outbound Routed dials that could cost you money, the risk of this setup is no higher than that of any other DID -> IVR setup.

EDIT: YOU NEVER WANT TO ATTACH A DISA ANYWHERE EVEN ADJACENT TO AN INBOUND DID CALL FLOW unless you know EXACTLY what you are doing! DISA is effectively an internal Dial Tone (think back to the old POTS days)…allowing the caller to dial ANYTHING that a normal phone extension can. THIS is a massive security risk for the obvious reasons. Just leave DISA alone. You’ll be glad you did. :wink:

Thank you TheWebMachine

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Thank You Marc and TheWebMachine. That works beautifully. I’ve worked with FreePBX from version 2 and did not know that functionality existed. This will also let me close some what I feel are holes in Direct Dial for other IVR’s too.


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