Unable to forward to external numbers

[josh@bascom]

Good Afternoon,

We're new to the 3cx world coming from other hardware-based PBX vendors. I'm testing a 3cx deployment for a new internal PBX. Important to note that we are a telco providing the SIP trunk connection directly to the 3cx box.
I've been able to provision the SIP trunk no problem. Got everything set on the softswitch, 3cx is communicating. Inbound and outbound dialing is working with 2-way audio. The issue is that we have a system setup for calling out voicemail notifications (I've read a lot on Google about how the 3CX doesn't support this natively) so I want to leave that existing piece of hardware in place for now. All I need is to forward the SIP calls inbound to the 3cx back out to a different phone number, and all should be well, that box will answer. I have 4 channels provisioned in the 3cx right now since we're in testing, and the SIP trunk matches. I have one extension programmed and on my desk. When I set up the SIP trunk to route to an external number on no answer, it give me a "[FLOW] Target endpoint for xxxxxxxxxx can not be built!" error. There is an outbound rule created (it's blank so that all traffic is routed out the SIP trunk I've handed to the box), and I can call the external numbers I'm testing directly from the extension.
When I check the SIP server, I don't see the outbound SIP traffic coming from the 3cx box. Am I missing something silly?

 

[leejor]

It sounds to be an outbound rule (perhaps restriction) issue. Do your OB rules have rules as to which extensions can use them? I'm assuming that the number you have programmed to forward to, is the same format that you dial from a set.

Have a read through...
https://www.3cx.com/community/threads/outbound-rules-for-forwarded-calls.72382/

 

[josh@bascom]

I think I misunderstood the outbound dialing rules portion. I looked over the link you sent, then I went in and modified my outbound rules. I believed that I could leave everything blank to make it a wide open, all outbound calls rule, but that was not the case. I changed the rule to say "Calls to Numbers with a length of" 10-11 and now the forwards are working.

 

[GeorgeP_3CX]

Hi @josh@bascom,

Please note that this might create security risks to the Phone System though. A call to any number with these digit length(10-11) will go through, since there are no more limitations to the outbound rule.

The best practise when you are trying to forward a call to a specific number from an external party, is to set the "Calls to numbers starting with prefix" the external number that you want the call to be forwarded to. This means that only calls to that number will go through and you can leave the rest of the fields empty.

Please find our guides regarding the outbound rules here for a better understanding:

• https://www.3cx.com/blog/voip-howto/outbound-rules-a-complete-example/
• https://www.3cx.com/3cxacademy/videos/advanced/configuring-outbound-routing/
• https://www.3cx.com/docs/sip-trunk-outbound-calls/

 

[leejor]

While in North America ( I assume you are located here), a local or national number is generally 10 or 11 digits, there are exceptions. The X11 numbers and in many places now, a range of 9XX (besides 911).

You could have a rule that handles all national numbers...11 digits beginning with 1, and a local rule (or more than one) that can "handle" 10 digit numbers beginning with the first number (or first two )of the local areacode(s).

You may also want rules that block calls to certain "premium rate" numbers, 1-900, and some Caribbean destinations, unless your provider offers a blocking service for calls above a set rate.