Incoming calls for unused DIDs - Can 3CX return a 404 to the SIP provider?

[KMorley]

Customer is running V20 hosted by 3CX. Customer has several DID numbers at the SIP provider which are not provisioned on the 3CX system. When calls come into these DIDs, 3CX is accepting with a 200 and the provider begins billing. Then 3CX does END CALL as it is configured to do.

If it was a few calls, a few cents a day wouldn't bankrupt anyone. But in this case, it's more like 50 calls per day and these do add up.

The SIP provider has stated that if we don't want to accept and pay for these calls, 3CX can just provide a 404 and no billing will occur. Is it possible to get 3CX V20 to return a 404 on calls that have no route?

 

[OlegR_3CX]

@KMorley Hi there.
No, if the trunk sends the call to the Phonesystem, and you have the number there and configured, there will be no option to manipulate it from our end to send a 404 reply.
Don't you have those options on the SIP trunk portal so if the number is not in use and you know it, let the trunk end the call before even sending it to the Phonessystem?

 

[KMorley]

Oleg:

Thank you for your reply.

To be clear, these are trunks the customer has in inventory that are not currently in use and are not configured in 3CX at all. When a call comes in, 3CX sends 200 to the SIP provider (Flowroute) accepting the call. 3CX then doesn't find any route and correctly does END CALL. The problem is that the SIP provider begins billing when it receives the 200 from 3CX. This results in a few cents charge for each call.

Some of these DIDs appear to have made it onto telemarketing lists and are being called at least several times per day. With the number of DIDs this customer has, it amounts to at least 50 such calls every day.

Flowroute does not offer any mechanism for refusing calls. Their technical support suggested routing the call to host 0.0.0.0 and that's what I've done at this point. But it seems like 3CX would have some mechanism for refusing calls. And ditto for Flowroute: it seems like there should be some mechanism on each end for refusing certain calls.

 

[UrielFoster]

Log in to the 3CX admin panel and go to the "Incoming Rules" section or a similar section where you can create incoming routes.
Create a rule that will trigger for all incoming calls with DID numbers that do not exist in your 3CX system. This can be done, for example, by specifying DID numbers that are not used in your system.