SIP Trunk Not Registering or Attempting Registration

[the131]

Hello,

Ran into a strange issue today with all of my 3CX clients that we support. Every one was showing that the SIP Trunk was unregistered. The strange part about this, was that 3CX did not appear to have ever attempted registration. There was no history, nothing in the logs, it was just unregistered. Any attempt to manually register with the buttons at the top did nothing, "Refresh Registration" and "Enable all" did nothing. The ONLY way I could get my SIP Trunks to register was to go into the SIP Trunk settings, click around, then hit "OK". Then it registered. On the last two I fixed I attempted to just go in, hit OK, which did not fix it. I actually had to go into the settings and click a few fields so that the system would actually "Save" the SIP Trunk (even though I changed nothing). Then it registered.

Obviously this is a huge problem and I am surprised nobody else is posting about it. I figured I'd post here in case any one else had this issue.

 

[Nickelpede]

We have been having issues since an automatic update on 8/15/2020.
I rolled back to .612 and registration still failed.
I changed the FQDN to an IP and Registration failed 1 hour 45 later.
I'm thinking of rolling back to something earlier.
Dang this is frustrating.

 

[the131]

One thing that fixed a few of my sites was to disable IPv6 in the SIP Trunk options. Go into your SIP Trunk, then choose "Options", scroll down to "IP Mode" and choose "IPv4". This worked on some sites. On other sites I had to do some more finagling. It definitely is not a full fix. The issue appears to have something to do with DNS and how 3CX is handling DNS, in particular how it handles failure to receive a response to DNS queries. Another thing you can try is to disable the "Alternative proxy" again in "Options" page. The goal is to limit the amount of DNS queries until it finally gets the responses it needs. Not sure why 3CX is having this problem but we actually see DNS requests going un-responded, on all of my sites.

After each change restart the SIP Service (Dashboard-->Services-->Sip Server) as that forces 3CX to do new DNS queries.

Another fix is to use IP Auth with your Sip Trunk provider. But in my case I also had to change the server to the IP address of the SRV record, as it still wouldn't resolve the server.

Apart from that the only way I can think of to force a fix in Windows would be to setup a local DNS server with the records you need, that seems pretty silly but that may work for some people.

 

[AWS2P]

For now I forced IPV4 in trunk options and reverted to sip domain in trunk setting and refreshed registration with success while yesterday it was impossible

 

[Nickelpede]

I have a Domain.I have internal DNS, but changed the 3CX computer to use 8.8.8.8 after several days of Registration failures using Internal DNS resolution.
The registration continued to fail.
I disabled IPV6 on the network adapter inside Windows 10 and selected only IPV4 in the SIP Trunk option settings.
I left the protocol at Any.
I should mention that registrations sometimes fails and retries a few minutes later and succeeds. Sometimes it doesn't.

 

[Avram Grossman]

Just letting you all know I have this issue as well. Client is VERY unhappy as no resolution after a few weeks. is an update/fix forthcoming from 3CX?

 

[Avram Grossman]

For now I forced IPV4 in trunk options and reverted to sip domain in trunk setting and refreshed registration with success while yesterday it was impossible

Where is the "trunk options" to be found?

 

[Saqqara]

Just letting you all know I have this issue as well. Client is VERY unhappy as no resolution after a few weeks. is an update/fix forthcoming from 3CX?

Have you raised a support ticket with 3cx, unless 3cx have all the logs, looked into the issue on the server - how do you expect 3cx to resolve the issue

 

[Avram Grossman]

I've tired almost all of the 'tricks' posted here. In WireShark I do not see ANY attempts to register with SIP Provider (Vitelity).

 

[Avram Grossman]

Have you raised a support ticket with 3cx, unless 3cx have all the logs, looked into the issue on the server - how do you expect 3cx to resolve the issue

I tried to raise a Support Ticket, but their website says I cannot post Ticket. How do suppose I can raise a Ticket when they prevent raising a Ticket?

 

[the131]

@Avram Grossman you have to do a wireshark capture and look for "dns" in the capture. You can look in this thread for instructions. Post a screen shot of the dns results in the wireshark capture. That is what my problem was/is. What I posted are fixes that have worked for me. I do agree there is still a bug, but I've at least gotten it to work. I've worked with 3CX on the issue and they have actually helped me with these fixes that I posted here.

 

[Avram Grossman]

Hi. I did a Wireshark capture a few times. Restarted 3CX SIP services. I do not see any traffic going out to my SIP provider (Vitelity) outbound.vitelity.net. I did not find "dns" in the search. Note: I have two systems both at 16.0.6.641. Both using Vitelity. Inbound traffic IS working to receive calls. Vitelity shows "offline" Side Note: changing inbound Rules does not change when call is received (goes to afterhours regardless of being disabled or not).

 

[AWS2P]

Where is the "trunk options" to be found?

 

[JohnS_3CX]

Hi. I did a Wireshark capture a few times. Restarted 3CX SIP services. I do not see any traffic going out to my SIP provider (Vitelity) outbound.vitelity.net. I did not find "dns" in the search. Note: I have two systems both at 16.0.6.641. Both using Vitelity. Inbound traffic IS working to receive calls. Vitelity shows "offline" Side Note: changing inbound Rules does not change when call is received (goes to afterhours regardless of being disabled or not).

DNS is for domain names. If you use an IP address as a registrar, you will not be seeing any DNS requests

 

[Nickelpede]

I have IPV6 disabled on the network adapter and IPv4 selected in the Trunk Options.
The last registration failure I got was yesterday at 5:35pm . I added the VOIP provider IP and DNS name to the Windows10 Host file. This should make no difference as I have set the Trunk options to a static IP.
But, There were no registration failures overnight.

 

[JohnS_3CX]

I'm having an issue currently with setting up Sip Trunking with ATT Reach and i wonder if this is part of the problem. I can receive incoming calls but no outbound. ATT keeps telling me they are noting seeing any communication on their end from our system. We use all ip addresses and no domain names.

Hi @JustinTaylor

Unrelated - you are clearly registered or IP-based please read here and start a new thread:
https://www.3cx.com/community/threads/information-to-provide-when-requesting-help.67558/

 

[Avram Grossman]

DNS is for domain names. If you use an IP address as a registrar, you will not be seeing any DNS requests

I am using the FDQN which pings back with the IP Address (to confirm it is correct).
Changed setting to IPv4 with no improvements. I'll keep trying ideas.

 

[Nickelpede]

14:42:52 Trunk L:10002(SIP_Provider_Name) has changed status to unregistered.
14:43:12 Registration at (SIP_Provider_Name) has failed.
14:45:12 Trunk L:10002(SIP_Provider_Name) has changed status to registered.
I am running Ping Plotter and there have not been any packets lost.
I guess I need to roll back to something before 16.0.5.612.
I have 16.0.4.493 on hand but gosh that's a bit way back.

I wonder if there is something in the Registry that is lingering after removal of 16.0.6.641.
I'm checking my system restore files and see how far back I can roll the registry.

Dang this is frustrating.

 

[JohnS_3CX]

So anyone facing this specific issue where the trunk cannot register, and wants to troubleshoot for specific details, should check the following:

1. Ensure you have built your trunk on our latest templated for supported providers. If you are not sure, delete and rebuild it (take a full backup first!)
2. Once it's ready if it still doesn't register, go to a 2nd tab and start a capture
3. Restart the SIP service and wait for a couple of minutes
4. End the capture and open it in wireshark.

If you filter for dns you should see the PBX IP send a query to your FQDN based registrar and most importantly, you should whether you receive any replies back for those queries. You should expect your DNS to reply to all those requests.

A detailed explanation what happens next can be found here (for whoever is interested in learning more):
https://www.3cx.com/docs/sip-trunk-dns-record-resolution/

 

[Nickelpede]

Hi JohnS_3CX,
I understand what you are asking people to perform.
I have made a capture with wire shark. I am beginning to analyze it.
What you are assuming is that there is a DNS resolution failure.
I have changed the settings to a static IP, which bypasses any DNS resolution and I still get registration failures.
Our system has been in place and working for quite a while, with no registration failures.
Once the update was installed the problems began.
I seriously doubt that this many users jacked up the DNS settings.
I wish I had know that automatic updates was on and the update was going to cause problems.

 

[AWS2P]

@JohnS_3CX
Hello, this morning i got trunk stay unregistred on 2 new PBxs (openip sip provider)
They are on premise windows 10 PBxs
they were using sip domain in trunk template, I tried first to replace with provider IP --> KO
Then selected trunk and press disable all, then enable all, then refresh register ->KO
Then restarted SIP service from console ---> KO
Then restarted PC ---> KO
Then redone enable/ disable all , Refresh then trunk register. OK

NOTA: I found on 3 windows pbxs on dashboard Outbound rules increase alone (for example Dashboard display there's 11 rules and there's only one). Same behavior on 3 different PBXs