3CX - with 3 different SIP Trunks to the same SIP Provider

[elcotrade]

Hy guys,
i am new to 3cx - i only have 2 working installations with about 20 phones running - everything is working fine. I am constantly learning to handle 3CX.
But now i plan to install a more complicated installation, where i have some troubles during planing.

As soon when i know how to build this, i will get some test numbers from my sip provider to test everything.
Heres my challenge:
I have one company with 3 different external numbers. For explanation i use this 3 numbers: +43001, +43002, 043003.
Our local SIP Provider (which is not supported by 3CX, but is working fine at the other 2 installations), told me, that i need to connect to three SIP Logins:

IP: sipproviderXYZ.at Port 5070
User= +43001
Pass= XXX
-> i get the calls from the provider to my external IP Port 5070

IP: sipproviderXYZ.at Port 5070
User= +43002
Pass= XXX
-> i get the calls from the provider to my external IP Port 5071

IP: sipproviderXYZ.at Port 5070
User= +43003
Pass= XXX
-> i get the calls from the provider to my external IP Port 5072

All three external Ports are getting forwarded to the 3CX SIP Port -> so receiving calls should work fine, also i there is no active UDP session.
And for outgoing calls the 3CX has to put all three Trunks to sipproviderXYZ.at Port 5070 BUT the SOURCE Port from the 3CX MUST be different +43001 from Port 5070, +43002 from Port 5071 ...


Is this possible? Is there a other way to solve this? Or do i have to talk the my provider that he has to handle the Trunks in an other way?
At the 3CX i will have 3 extension groups with different "incoming signaling group and differnet working hours etc" So one big company which wants to act to the outside like 3 small companys.

Thanks for your help!
Manuel

 

[cobaltit]

You are over complicating things. If you are using registration-based trunks the registration is used to identify which trunk is in use, so there's no need for calls to come in on a different port or go out from a different port.

 

[elcotrade]

Yes i now, but I am still learning, so sorry for stupid questions.
So you mean, as long as the UDP Session to the SIP Trunk is open (which should be everytime when Registration@3CX and the UPD Timer on the Firewall is configured correctly) the Port Forwardings etc. should never be used. -> Thats clear for me, for incoming calls. The PAT is only neccessary if there is a problem with the active UDP session, to allow my provider to put the calls anytime to me.

But in the scenario, the Origin Port for outgoing calls from 3CX will be 5060 as definded during installation. Is then my provider able to different between the 3 Trunks?

I think that my provider is complicating things here..
But i will test this with some Test-Trunks and then i will see..

 

[Saqqara]

But in the scenario, the Origin Port for outgoing calls from 3CX will be 5060 as definded during installation. Is then my provider able to different between the 3 Trunks?

Yes, they will as you will route outbound calls down the correct sip trunk - https://www.3cx.com/docs/manual/sip-trunks/#h.szzyf4k5tmol

We have multiply sip trunks from the same provider using username and password , all using port 5060.

 

[elcotrade]

Ok thanks. That was my inital plan to do this, until my provider told me the other things.
I will try this on my Test-Appliance.
Thanks for your help!

 

[JohnS_3CX]

Hi @elcotrade

This article should be your go to https://www.3cx.com/docs/ports/

The port forwards must be used, and they must be full cone NAT.

Do not rely on the firewall keeping the session alive for you unless you want to spend your days troubleshooting instead of enjoying the use of your system. We have a built in firewall checker you can use after the the firewall is set up correctly.

 

[elcotrade]

Hy, ok. thats exactly the way I used on my other 2 installations. And it works fine.

So i have no solution for this special case, or let me say requirements of my SIP Provider.

Can you tell me whats the usual way when someone has more than one SIP Trunk from one Provider which registrates to the same SIPFQDN and Port?

 

[JohnS_3CX]

Your system does not mind how many providers/trunks it has. It will listen to port 5060 for all of them, and will use the RTP range for audio across all of them.

As for sending calls/registering you can configure individual ports each trunk, they don't have to all be 5070. Just play around with the trunk settings section, you can see the options you have there

 

[elcotrade]

Hi, yes thats all clear to me.
But my provider says that i have to connect each trunk to port 5070 for registration. And 3CX should use as Origin Port for outgoing calls for each Trunk another port which isnt the same which is used for registration. But thats not possible with 3CX because it seems like its not normal how my provider works. So I test it and if i have problems i talk to my provider to find a solution.I don't understand why my provider needs 3 different origin ports..their SBC should be as smart enough to see which outgoing extension is calling..

Thanks!

 

[JohnS_3CX]

You may have too look at supported providers then for this project.
https://www.3cx.com/partners/sip-trunks/