3CX V20 – FQDN Resolves to Incorrect Public IP, Web Client Unreachable

[Volfcommunications]

Hello 3CX Community,

We are experiencing a DNS issue with our self-managed 3CX V20 Update 9 (Build 995), Basic Edition installation.

FQDN: xxxx.sd.3cx.us

Correct server public IP: 4.xxxxxx0

Current authoritative DNS A record: 9xxxxxx1

We have confirmed the following:

• The server's network interface and outbound public IP are both 4xxxxxx0.
• HTTPS responds with HTTP 200 OK when connecting directly to 4xxxxxxx0 using the correct hostname.
• Google DNS (8.8.8.8), Cloudflare DNS (1.1.1.1), and the authoritative Cloudflare nameserver all return 9xxxxxxx1.
• All 3CX services are running.
• Refreshing the 3CX licence did not correct the DNS record.

As a result, our employees cannot access the Web Client or use their welcome-email activation links.

Since this is a 3CX-managed FQDN, is there a supported way to trigger a DNS update, or could a 3CX representative investigate the incorrect A record?

We would appreciate assistance resolving this without interrupting our production PBX.

Thank you.

 

[Alejandro_3CX]

Hi @Volfcommunications please edit your post to remove sensitive information, such as your FQDN and public IP addresses.

Regarding this issue I can notice that the subscription is installed in two different servers. To resolve this:

• Ensure only one machine remains active; the secondary or test server must be turned off or deleted.
• Update network settings on the active machine:
  • Navigate to Advanced > Network, select Dynamic IP, and apply the changes.
  • Go to Dashboard > Services and restart the 3CXDatabaseServer. This forces the system to detect your current public IP and update your FQDN.
• Once the service has restarted, go to System > License and click Refresh License Key.
• Flush your local DNS cache. Note that full DNS propagation may take a short time before the FQDN resolves to the correct public IP.

Have a good day!

 

[Volfcommunications]

Thank you, Alejandro.

Could you please confirm how we can identify the second server associated with our subscription?

We want to ensure we keep the correct production server active without disrupting our phone system.

Would you be able to provide the second server's details through a private channel?

Thank you for your assistance.

 

[Alejandro_3CX]

Thank you, Alejandro.

Could you please confirm how we can identify the second server associated with our subscription?

We want to ensure we keep the correct production server active without disrupting our phone system.

Would you be able to provide the second server's details through a private channel?

Thank you for your assistance.

There was an on premise deployment under the hostname AriaPCDesk then the same say you installed on the cloud with OVH.

So check which one is the active and remove the other one.

Have a good day!

 

[Volfcommunications]

Hi Alejandro,

Thank you very much for your quick response and for identifying the second installation. I really appreciate your help.

I can confirm that AriaPCDesk is my Windows desktop computer, and I still have access to it. I'll check the old installation before making any changes.

I also wanted to ask about my original forum post. As you advised, I'd like to remove the sensitive information, including the FQDN and public IP addresses. Unfortunately, there is no Edit or Delete option available for my original post.

Should I request that the entire thread be deleted, or would a moderator be able to edit the original post and remove the sensitive details?

Thank you again for your assistance!

 

[Alejandro_3CX]

You should see the EDIT button in your post.

 

[Volfcommunications]

That's exactly the issue. I can see the Edit and Delete buttons on all my replies, but neither button appears on my original post (#1).

I've checked both the top and bottom of the original post, and only the Report button is available.

Could you please help me remove the sensitive information from the original post, or ask a moderator to edit it?

Thank you!

 

[Volfcommunications]

Hi Alejandro,

Thank you again for your assistance.

I've now stopped and disabled all 3CX services on the old Windows installation (AriaPCDesk).

The active OVH server is running normally, and its 3CX dashboard correctly displays the static public IP.

However, the authoritative DNS record for our 3CX FQDN still points to the old IP address, even after disabling the previous installation.

Could you please advise how to force the 3CX-managed DNS record to update, or check whether the FQDN is still associated with the old installation?

I'd prefer to avoid interrupting our production PBX.

Thank you for your continued help.

 

[Alejandro_3CX]

Hi Alejandro,

Thank you again for your assistance.

I've now stopped and disabled all 3CX services on the old Windows installation (AriaPCDesk).

The active OVH server is running normally, and its 3CX dashboard correctly displays the static public IP.

However, the authoritative DNS record for our 3CX FQDN still points to the old IP address, even after disabling the previous installation.

Could you please advise how to force the 3CX-managed DNS record to update, or check whether the FQDN is still associated with the old installation?

I'd prefer to avoid interrupting our production PBX.

Thank you for your continued help.

Please perform the actions mentioned at the beginning:

• Update network settings on the active machine:
  • Navigate to Advanced > Network, select Dynamic IP, and apply the changes.
  • Go to Dashboard > Services and restart the 3CXDatabaseServer. This forces the system to detect your current public IP and update your FQDN.
• Once the service has restarted, go to System > License and click Refresh License Key.
• Flush your local DNS cache. Note that full DNS propagation may take a short time before the FQDN resolves to the correct public IP

 

[CentrexJ]

Hi Alejandro,

Thank you again for your assistance.

I've now stopped and disabled all 3CX services on the old Windows installation (AriaPCDesk).

The active OVH server is running normally, and its 3CX dashboard correctly displays the static public IP.

However, the authoritative DNS record for our 3CX FQDN still points to the old IP address, even after disabling the previous installation.

Could you please advise how to force the 3CX-managed DNS record to update, or check whether the FQDN is still associated with the old installation?

I'd prefer to avoid interrupting our production PBX.

Thank you for your continued help.

Restart the 3CX at OVH and it should update the FQDN IP Address.
Also on the "AriaPCDesk" Windows PC if you need to connect to 3CX make sure you review your host entry and delete the fqdn.

 

[Alejandro_3CX]

So far we have not received any FQDN change on our servers.

So let’s make it easier from the network menu set Static IP —- enter the correct IP and apply the changes.

In this way you can also trigger the IP update for the FQDN

 

[Alejandro_3CX]

Hi @Volfcommunications the FQDN has been updated and web client page is reachable.

Please make sure to delete your DNS cache and give it a try.