Solved AT&T SIP IPFLEX BVOIP

[VPCIII]

ATT is no help, they say they support 3CX but they have no info on setup. Has anyone had luck with this SIP provider.. We cannot get outgoing calls to work at all. Wireshark trace shows connection refused at the ATT IP address, incoming calls are fine. Not a routing issue on my side the request it getting to the provided IP. They are saying there is no authenticatioin, the physical connection to the ATT cisco router is the authentication..
Of course they give you 4 IP address 2 signalling and 2 media, you have to set up separate trunks to use all and I have a separate NIC hooked strait to a Cisco Router that is how they hand of the SIP service not over the internet connection. See attached wireshark
Any thoughts would be greatly appreciated..

 

[eddv123]

Hi VPCIII,

I find most of the big brand providers for 3CX are like that, they have gone through the interoperability testing but dont know enough to support you, so you are not on your own on that one.

What is the response coming back from them? 403 forbidden or something like that?

 

[YiannisH_3CX]

Hello @VPCIII

I have deleted the captures you posted as they contain sensitive information. You should never post whole wireshark captures in a public forum.
From the capture however i can see the invite leaving the PBX and going to the CISCO but nothing after that and there is no reply back. Has AT&T confirmed that the calls are reaching them?

 

[VPCIII]

Hello @VPCIII

I have deleted the captures you posted as they contain sensitive information. You should never post whole wireshark captures in a public forum.
From the capture however i can see the invite leaving the PBX and going to the CISCO but nothing after that and there is no reply back. Has AT&T confirmed that the calls are reaching them?

Thanks for deleting, guess I should have masked the public IP's and DINs but I didnt think they were accessible on the public side of the Cisco Router. ATT well you wait over an hour to talk to them then you go through two or three, people waiting for them to do what seems like internet search, and come back and say these setting work with other PBX systems.. They are just horrible about it. We are stuck with them, b/c well SIP is practically free with the fiber based 1Gb internet.
They have said its not getting to the Cisco router even after seeing the wireshark which is obvious even with my limited knowledge and is super frustrating.
I believe the crux of the problem is in the way they are set up. They give 2 signalling ips telling you to set up two trunks simple enough but then they give you two media ip's for the audio and the 3CX ATT template & system for that matter doesnt seem to be set up to send the media to a separate IP. It doesnt seem like any of the other SIP service templates are set up that way either...Some one has to have come across this..

 

[YiannisH_3CX]

You should only need the signalling IP's to set up the accounts as the media IP's are negotiated in the SDP part of the Invite so that should not an issue especially since incoming calls work.
Regarding outbound call, do you have access on the cisco router so you can run a capture there?
That should tell us where the issue is and if the calls are reaching the router.

 

[VPCIII]

No access to the Cisco Router and they have refused to give it. Salesman said he would get me the password but has not come through. So no access.
The information about the Media IP's is helpful I will stop going down that path with ATT, and stick firmly to the connection not going past the first Local IP of the Cisco Router..
Thanks,
Vincent

 

[YiannisH_3CX]

If you manage to get the password of the router it would be very interesting to see why the calls are not going out. Please update the thread if you find a solution

 

[VPCIII]

I called AT&T 3 times today and spent about 3-hrs on the phone, just wouldn't listen, I was told problem was on my end multiple nics, routing tables, firewalls. The third call I got the right guy, he went over the router setting and the signalling port was blocked by firewall. 5 min. with the right engineer problem solved.

Thanks for all your help !

 

[YiannisH_3CX]

Glad to see the issue has been resolved and thank you for updating the thread. I am sure someone else will find the info useful.