How to change the FQDN?

[AxelLVW]

Hi everyone,

I'm getting an E-Mail "Lets Encrypt SSL certificate was failed to renew. Error: PostInstall.LetsEncrypt.LetsEncryptRegistrationException: FQDN already in use. Please choose another one."

But my little problem is, that I don't know how to chose another FQDN, since it seems to be set for life. How do I change it?

Best regards
Axel

 

[eddv123]

Hi AxelLVW,

This issue is only apparent for 3CX Supported SSL Cetificate and FQDN as you are probably aware.

Someone else has used the same FQDN as you have (or you have installed it in 2 different locations) that much is obvious. However what I would expect is that you would see a clear error when installing this PBX instance in the first place (not get an email after the event).

Please check:

* When did you install this instance of 3CX Phone system.

* When installing the system did you have no issues or errors.

* If you do an nslookup of this FQDN, does it resolve to the correct public IP or another.

* Are you aware of any other sites or times you would of used this FQDN (for example building the 3CX system back at your own offices and moving a backup to site).

For a solution to this issue - see altering the FQDN options and scenarios in these guides:
https://www.3cx.com/docs/fqdn-management-allocation/
https://www.3cx.com/docs/fqdn-management-allocation/

 

[sip.bg]

Backup without SSL and FQDN, uniinstall, install again 3CX with restore from backup, enter your license key and new FQDN.
Before that you need to release old FQDN from current license in 3CX customer portal.

 

[AxelLVW]

I tried the backup-solution. Problem with this is that the system doesn't use DHCP anymore but it melts the IP it had during the restore process permanently into the system... I don't know why but that is what the 3CX Support told me.

 

[eddv123]

Yes, the Local IP of the system is "sticky" and should not be changed. You will need to do a backup and restore to assign an new local IP address.

Additionally don't ever use DHCP for local IP allocation of the PBX- always static (however you can reserve your DHCP IP in your server if you really wanted). If not and your DHCP address were to change you would be in for some real issues.

 

[AxelLVW]

And how do I change the IP address after the restore?

 

[eddv123]

See this thread here:
https://www.3cx.com/community/threads/changing-internal-ip-of-server.50183/#post-204050

Response from 3CX Support.

 

[sip.bg]

You can change IP address only during installation from 3CX ISO and not afterwards. For this purpose you should not have DHCP enabled in your network, or to have IP address reservation based on MAC. When not having DHCP enabled, you will get an error and will be asked to enter IP address manually -- you should enter it as (example): 10.10.10.10/24, gateway (example): 10.10.10.1 and DNS: 8.8.8.8 (obligatory).
Hope in next service pack of 3CX this will be fixed and dialog about configuring IP address (static or DHCP) will be shown always.

After new installation and restore are complete, you need to reprovision all of your phones to new address, unless local FQDN is used in your network (and telephone use it, instead of IP address of SIP server.