Forwarding External Calls to Mobile

[jeffgeno]

I'm having trouble getting calls from external numbers to successfully forward to a user's mobile number. I'm using Twilio as my SIP trunk provider and it's the only service for outbound calls from 3cx. All extensions have a DID and have been set to immediately forward calls to the mobile number.

When calling from an outside number with forwarding on, Twilio refuses the call because 3cx is trying to send the original caller's number as the caller ID. It's obviously not one of our numbers, so it's blocked because it's seen as a spoofing attempt.

When I try using the 302 deflection option, Twilio also rejects the call. They don't support redirects.

I thought the Rebound option would do what I need, but when I call from the outside the line rings for a second and I'm transferred to voicemail. The call log shows IVR (IVR Forward) as the From number and the mobile number as the To, but it just says "Not Answered." It seems like it's trying to find out outbound path for the call and failing, but I can't figure out why.

My Outbound rules are really basic. Just adding the required digits in case someone calls a 10 or 11 digit number and sending it all to Twilio.



How can I set this up so it works? I understand I won't get the right caller ID, but Rebound should do what I want.

 

[Evolute IT]

Why not just use the mobile app instead of forwarding the call? You would bypass the CID problem and also save some SC.

 

[jeffgeno]

Why not just use the mobile app instead of forwarding the call? You would bypass the CID problem and also save some SC.

That's where we're going to end up eventually. But we're doing a slow roll out and are starting with forwarding so there's no end user action required. It would also be good to have this working for one-off forwarding needs in the future.

 

[leejor]

There are a number of setting in the outgoing trunk options that deal with where caller ID is taken. Changing these, however, can affect other calls, or stop all outgoing calls on the trunk. Make note of original settings before making changes. Probably one of the setting currently using OriginatorCallerID.

https://www.3cx.com/community/threads/caller-id-on-forwarding-external-call.47746/

 

[jeffgeno]

There are a number of setting in the outgoing trunk options that deal with where caller ID is taken. Changing these, however, can affect other calls, or stop all outgoing calls on the trunk. Make note of original settings before making changes. Probably one of the setting currently using OriginatorCallerID.

https://www.3cx.com/community/threads/caller-id-on-forwarding-external-call.47746/

I tried that one out. If I change it to OutboundCallerID, it works to forward calls from internal lines, but external calls still fail. It still sends the caller ID from the original caller rather than the extension doing the forwarding. I don't want to override every single call with a single caller ID. I'd just like the one for forwarded calls to appear to come from the called number rather than the calling number.

 

[leejor]

It's been a while since I went over all of the caller ID options, but as I recall there were multiple instances of OriginatorCallerID being used, as well as multiple options to change the field to. I would wait until after hours before experimenting with these as it can severely affect all calls. You may fix one issue, but cause others.

 

[David Gevaerts]

We had the same here.
It is working OK for us now, because we use the away state an have the "Use Call Deflection" checked for the external calls. I hope this will help you to.

 

[jk2]

We had the same here.
It is working OK for us now, because we use the away state an have the "Use Call Deflection" checked for the external calls. I hope this will help you to.

Are you also using Twilio?

 

[complex1]

When calling from an outside number with forwarding on, Twilio refuses the call because 3cx is trying to send the original caller's number as the caller ID. It's obviously not one of our numbers, so it's blocked because it's seen as a spoofing attempt.

I am afraid you never will get this to work with this provider.
You need a provider who allow any CID. (Clip No Screening Support)

 

[Evolute IT]

I am afraid you never will get this to work with this provider.
You need a provider who allow any CID. (Clip No Screening Support)

Actually, there's the rebound feature that allows the PBX to tell the person who is calling when you can't use the original CID.

 

[complex1]

Yes, but Rebound feature isn't working either... as I understand.

 

[JohnS_3CX]

I am afraid you never will get this to work with this provider.
You need a provider who allow any CID. (Clip No Screening Support)

You might have to enable this feature on the provider's portal first.

 

[CharlieKSDG]

I just wanted to chime in to mention that we are trying to accomplish the same thing as @jeffgeno We are trying to forward internal and external calls to a cellphone number when an extension is "Away" or in "DND" mode.

Some environment specifications:
- 3CX Enterprise 16.0.4.493 (Debian 9.6 x64)
- Yealink T48S and T46S (FW 66.84.0.95)
- Twilio SIP Trunking setup as per 3CX documentation

I've noticed there is a setting in the Twilio SIP Trunk that refers to forwarding, but I've tried it to no avail.

Twilio Error Log:


Twilio SIP Trunk Settings


Twilio Forwarding Option

 

[leejor]

The Twilio forwarding would have nothing to do with calls, being presented to 3CX, then forwarding to an outside number, as the forwarded leg is simply seen by the provider as an outgoing call. Providers that offer forwarding will route calls, destined for the number that you are subscribed to, to another destination for various scenarios, such as a registration failure, or invoking the feature. This type of call would never be seen by the PBX.. Not much difference from the way the residential forwarding feature works.

 

[CharlieKSDG]

@leejor I had a feeling that setting was not going to accomplish what we're all looking for. From reading this thread, it's starting to sound like 3CX does not support this feature with this supported SIP Trunk provider.

@JohnS_3CX and @complex1 mention that we might be able to get Twilio to accept these call forward requests if we essentially disable Twilio's CID authentication. I don't think that's the most secure way to handle this (especially with the CRTC's recent plans) and I'm not sure if it's even technically possible.

Is there no way to get 3CX to send my primary DID (instead of the CID of the phone calling in) when using the "Announce Caller (Rebound)" feature?

 

[jeffgeno]

I ended up giving up on it and switching to Flowroute from Twilio. Even if I could get it to work, the solution doesn't scale if you need to jump through a bunch of hoops for every forwarded extension.