Solved: Impact in change the DNS's Ip Address on the Cisco UC 14 and UCCX 12.5

csrlima · ‎03-09-2023

Hi team, i know how to change the dns of CUCM 14 and UCCX 12.5 ( set network dns .... ) but i dont know in this version if i need to reboot servers (CUCM is a cluster of 3) and uccx is standalone) and the correct order to do it. i dont find similar documents

This company is changing DNS IP Addresses (AD servers) and i need to avoid problems with Collaboration Services, so:

i have to change CUCM dns

i have to change UCCX dns

i have to change Expressways DNS

I have to Change LDAP server in CUCM

i have to change ip helper address in voice phones vlans ( because DHCP server is changing with AD) and also have to change DNS servers in DHCP Voice Pools.

Am i missing something?

Best Regards

b.winter · ‎03-09-2023

No, you don't need to reboot anything of your list.
And no, there is no "correct order". Just do it.

For the phones, you should probably decrease the lease time, before you change it. Because even if you have changed the DNS server in the DHCP pool settings, the phones will still have the old IP. And it can take days, until the request a new IP (with the new DHCP-settings).

And probably you need to do it in a maintenance window, because you cannot change the DNS servers at the same time and therefore, in the second where to DNS server IP changes, anything of your list will still point to the old IP and will not be able to resolve or provide DHCP.

View solution in original post

b.winter · ‎03-09-2023

No, you don't need to reboot anything of your list.
And no, there is no "correct order". Just do it.

For the phones, you should probably decrease the lease time, before you change it. Because even if you have changed the DNS server in the DHCP pool settings, the phones will still have the old IP. And it can take days, until the request a new IP (with the new DHCP-settings).

And probably you need to do it in a maintenance window, because you cannot change the DNS servers at the same time and therefore, in the second where to DNS server IP changes, anything of your list will still point to the old IP and will not be able to resolve or provide DHCP.

Nithin Eluvathingal · ‎03-09-2023

You don't need to restart the servers if its just DNS ip address.

Dont you have IMP, unity gateway etc where also we configure DNS ?

As @b.winter mentioned do this on maintenance Window. And for the phones to take the new DNS IP reducing lease time will be a good option.

csrlima · ‎03-09-2023

I dont have to worry about certificates also?

I dont have to worry about UCCx licenses also?

About DHCP and ip phones, as far i have the 2 DNS servers running in parallel for a while, best is do it as soon as possible.

Thanks for your advices and suggestions

Nithin Eluvathingal · ‎03-09-2023

Certificates will not be affected by the DNS change.

I hope for UCCX you are using smart licensing. And there wont be any impact. Even if there is an issues reregsier will solve the issue.

Roger Kallberg · ‎03-09-2023

In what way would a change of DNS server IP(s) affect certificates?

Scott Leport · ‎03-10-2023

Hi there,

I think that the certificates would only be a concern if you were changing the domain name. From your original post you don't mention it, so I guess that's not required?