Direct SIP - Cannot receive incoming calls

[Alan9846]

Hi All,

We have a 3CX customer that wants to be able to receive Direct SIP calls.

The 3CX server is working fine, and has been for some years. It is fully updated and on the latest Version 18.0 (Build 461), running on Debian on-premises.

We have turned on the option in 3CX (under Network - FQDN) and set the Local SIP Domain to be the same as the FQDN (clientname.my3cx.nz).

The customer uses a non-standard port for SIP (35060) as their ISP doesn't allow incoming connections to 5060 (I believe they sell their own VOIP service and reserve 5060 for that, but our customer does not use the ISPs service at all - they have a register based account with a SIP Trunk Provider). The FQDN resolves fine, and if I telnet to the FQDN on port 35060, something answers, so I am guessing there is no firewall issue (the firewall checker is green).

I have added a SIP ID to a test extension 001 ('admin').

I have tried testing by adding a contact in my phone (Android) as follows:

[email protected]:35060

and also

[email protected]:35060

but my phone just shows 'Calling' - it never actually connects through to 3CX.

Just in case, I also tried on the 'Secure SIP' point (35061 in this case), but still nothing.


I have turned up the logging level to 'verbose', purged, tried calling in, and then searched for anything with the IP address I am calling from, but nothing shows at all. Not sure if that means anything?

I guess it is possible that the issue is with my phone (Android), rather than 3CX. To confirm whether that is the case, is there any sip destination test service that I can call from my phone to make sure that works? Similarly, is there anything out there (website maybe) that allows you to call a sip address to do a test? I have searched via Google, but haven't found anything so far - maybe I am not searching for the right things and / or I am not recognising something that would do either of those tests though.


Any suggestions welcome, and I am happy to re-confirm any settings you think I might have gotten wrong.


Thanks,

Alan.

 

[Alphabetic]

Have you created relevant DNS Records?

https://www.3cx.com/docs/direct-sip/

 

[Alan9846]

Hi kieferschild,

Have you created relevant DNS Records?

https://www.3cx.com/docs/direct-sip/

No - I had figured that, since the customer is using a 3CX.com provided FQDN (under my3cx.nz), that the SRV records would either be created automatically, or were not possible to create?

Is that the issue?

If so, how do we create those records under my3cx.nz when only 3cx.com will have access to them?


Thanks,

Alan.

 

[Alan9846]

On the matter of the SRV DNS entries - just wondering how would that make a difference?

The connection string I am using is:

SIP:[email protected]:35060

The only thing in there that needs to be resolved is the hostname, and that definitely works (otherwise the customer would be having all sorts of other issues with 3CX, plus I specifically checked that it correctly resolves as well).

I did try substituting the IP instead, so that DNS is (I am thinking) completely out of the picture, and that didn't worth either, but I had not expected it to, since 3CX would be checking the domain of the incoming call.

For what its worth, I also tried calling out from my phone on different networks (my home which is on fibre, and via mobile data) - no difference there either, but at I noted above, I can telnet in and something (presumably 3CX) is answering.


Thanks,

Alan.

 

[cloidhamer]

I haven't set this up, but I think perhaps you are thinking about it incorrectly.

To set this up you have to have control of the domain you are using and you don't control clientname.my3cx.nz. If you use some of the look up tools on mxtoolbox.com you will see that clientname.my3cx.nz only has basic DNS resolution, and sip.clientname.my3cx.nz doesn't resolve. So you can't use the domain assigned to you by 3CX.

I think you want the SIP address to be the same as the users email address, which the domain users / customers can control. The instructions seem to be showing you how to setup the DNS internally on your customer's domain not the domain of the 3cx server. Also you I think would have to setup an A record on the domain provider, sip.yourdomain.com so external DNS queries will resolve.