Best practice changing the local IP address of on prem 3cx server

[rlynch@lockhartcadillac]

Hello,
I have been doing some reading on this but wondered if there was a best practice out there for changing the internal/local IP address of my on prem 3cx server? They originally just put it all on the same network as everything else, and for multiple reasons I need to move the 3cx server and the IP phones over to its own subnet/voice vlan. I was wondering if there is just a certain backup to run from the 3cx portal, and then just recover that backup to the server with the new internal/local IP address? I also have about 50 yealink t4w's all provisioned on the current server IP, whats the best way to bring those up on the new 3cx server IP address? Remove every single one from the ext's in current 3cx portal, factory reset them all and re provision them as they are hooked up to that new voice subnet? I appreciate the help if anyone has been through this before. Thanks

 

[SteveITS]

See https://www.3cx.com/community/threads/local-lan-change.81723/post-377738

For the phones, first change them to have "Select Interface" be the hostname and reprovision, and use split DNS to set the LAN IP.

 

[rlynch@lockhartcadillac]

Thanks for the reply, would like to continue to use the local ip of the server as I have many phones connected over a vpn provisioned using that local server IP. However if thats not really a good way to do this local IP change, maybe i'll go a different route.

 

[SteveITS]

I'm not following which part won't work? If you set up split DNS then you're controlling which IP is used via DNS. Set the TTL on the internal hostname to 30 seconds, change the 3CX LAN IP, and change DNS.

 

[rlynch@lockhartcadillac]

I think that way is great, im wondering how my phones on a different network in a different location are going to resolve the hostname over that vpn? There aren't dns servers at the remote locations. They currently use the provisioning link with the 3cx local ip in it to come across and register with the 3cx server.

 

[SteveITS]

Oh I see. Well per other 3CX posts split DNS is [going to be?] required. Can the phones use DNS over the VPN? They need the VPN up for the phones to work anyway...

 

[rlynch@lockhartcadillac]

Gotcha. From what the post looks like you can change the local server IP, reboot, and 3cx will recognize and alert you that the IP has changed. From rebooting, the services have been rebooted, and now that new local IP should show in the provisioning links and anywhere else in the templates where the old local IP was. So that takes care of server. The phone was the other part right. I figured may have to delete each phone from the exts in the admin portal, factory reset phones, and then as the phones are brought on on the new subnet, the same new subnet that the 3cx server is now on, you'll start to see the phones populate back into the portal, and can then reassign them to the exts. Thats kind of what i was seeing anyway. On the remote phones same thing, wipe them, and then jump in the actual phone web gui on those remote phones and past in the new provisioning link that contains that new local IP. Which is basically same way I provisioned those remote phones the first time, just paste provision link into the phones web gui, reboot phone, done.

 

[adn77]

If you control the DHCP server on the remote site you could try using option 66 to propagate the new provisioning address.

Alex

 

[SweetAction]

Gotcha. From what the post looks like you can change the local server IP, reboot, and 3cx will recognize and alert you that the IP has changed. From rebooting, the services have been rebooted, and now that new local IP should show in the provisioning links and anywhere else in the templates where the old local IP was. So that takes care of server. The phone was the other part right. I figured may have to delete each phone from the exts in the admin portal, factory reset phones, and then as the phones are brought on on the new subnet, the same new subnet that the 3cx server is now on, you'll start to see the phones populate back into the portal, and can then reassign them to the exts. Thats kind of what i was seeing anyway. On the remote phones same thing, wipe them, and then jump in the actual phone web gui on those remote phones and past in the new provisioning link that contains that new local IP. Which is basically same way I provisioned those remote phones the first time, just paste provision link into the phones web gui, reboot phone, done.

You can skip the wiping part of this and just remote into the phone and update the provisioning link to the new IP.

But you should setup split DNS and use the DNS servers over the VPN.

What do the computers / other devices that are remote use for DNS now?

 

[rlynch@lockhartcadillac]

Thanks for the reply, the remote devices just get dns assinged from the router doing dhcp. I do see what you guys are saying now about split dns. Im glad to hear though that changing the IP on the local server and rebooting is all that needs to be done on the server part. Sounds like after changing the local server IP on the server, 3cx recoginzes that and makes all those changes to templates, provision links, etc... I guess I was personally avoiding the split dns for now only because we dont use dns servers currently, and they only use ip phones on the local networks. They arent signing into the web portal, cell phone app, etc... so for me in this environment, its always been eaiser to choose "use local IP in the provisioning link" during the initial 3cx setup, and provision all the IP phones using that local 3cx server IP. I do get how the split dns is useful though and maybe i'll just have to end up going that route. However, the only time our users need to resolve the public fqdn, is when they are outside the network with the mobile 3cx app, and that is in place working just fine. Thanks for all the replies though, much appreciated.