FQDN issue in phones connected to 3CX

[Pete Gazda]

I have a few SIP devices that I want to connect to PBX v15.5

In a Yealink phone, Zoiper or any SIP device, If I place the IP address in server information, life is good and everything works fine.

If I place test.myfqdndomain.com and point to that IP address I get a 603 Rejection error

If I do the same thing in Freeswitch server, it works either way.

Is it possible to fix this? I would like the ability repoint without going into multiple devices.
I DO NOT want to use a 3CX FQDN for point to a known IP

 

[eddv123]

Hi Pete,

Firstly have you followed this guide? It would be a good start: https://www.3cx.com/docs/fqdn-ssl-certificate-v15/

Also what happens when you nslookup your FQDN does it resolve correctly ?

You should be using your FQDN publicly in this format: https://myfqdn.3cx.com:5001

Obviously the 5001 port is whatever you selected during install.

 

[Pete Gazda]

Hello,

This is for phone registration only.

for example:
Server IP could be 64.84.17.100
I set a custom dns on my domain for phones.mydomain.[com] and point to 64.84.17.100

I can then ping phones.mydomain.[com] and it does resolve to 64.84.17.100
I go in my Yealink phone and under server host I enter phones.mydomain.[com]
I enter credentials and the phone DOES registers no problem.

The problem arises when you place a call. It get a 603 rejection error.
If I go back in the phone and enter server host 64.84.17.100 the phone registers and the call completes no problem.

For testing I tried on Epygi and on Freeswitch and the calls complete with no problem if the phone uses phones.mydomain.[com] I also tested on 2 servers running 15.5 and 1 on v15 with same result.

Please try creating an A Record on your domain and use that in the phone. Can you replicate on your side? I will try the same here but use the 3CX FQDN.

Thank You.

 

[Pete Gazda]

Ok, I tried with the 3CX Fqdn and it works. 3CX seems to only accept it's own FQDN in the SIP string 2402@customer.tx.3cx.[us] which still resolves to 64.84.17.100 (example only) but will not accept [email protected].[com] even though an A record entry is valid for 64.84.17.100

 

[eddv123]

You should be able to use a 3CX FQDN or your own without issue.

What version of 3CX License are you using as custom FQDN is only available for certain versions ?

 

[YiannisH_3CX]

Hello @Pete Gazda

You can use your own FQDN and manage it through your own DNS however you need to provide this FQDN during the installation of the system. If the call arrives at the system from an unknown FQDN the system will reject it.