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[CUCM] Change DNS server IP


How can I change the DNS server IP on the CUCM? Can i change it over the Web Gui ?




18 Replies 18

Mohammed Khan
Cisco Employee
Cisco Employee

you cannot change DNS IP thru GUI, CLI is the only option

Refer below command

set network dns

This command sets the IP address for the primary or secondary DNS server.

Command syntax

set network dns { primary | secondary } ip-address

Hi Mohammed,


What i need to do in case to change the DNS ?

set network dns primary

Command will overwrite the existing DNS Server IP.

Do i need to reboot the CUCM service?

Reboot is not required,

this command causes a temporary loss of network connectivity. If you change the IP address of the DNS server, you must restart Cisco Tomcat.

Does this mess around with the license side of things? DNS change should be pretty straight forward right? 

Jaime Valencia
Hall of Fame Cisco Employee Hall of Fame Cisco Employee
Hall of Fame Cisco Employee

Only if you're running 8.x and below it would change the licenses.



if this helps, please rate

Hi Jamie,

Do you know if we have to restart all services or just tomcat?

We simply want to point our Cucm10x to a new internal DNS server.

Thanks Adam

Gordon Ross

Changing the DNS settings may cause the server to reboot. It will also affect the license MAC that licenses are tied to.


Please rate all helpful posts.

Im talking about changing the DNS of the interface of call manager. I don't understand how that would be tied into licensing? I would have thought it was just using DNS to resolve other servers in the cluster. 



admin:show network eth0
Ethernet 0

DHCP : disabled Status : up
IP Address : 1xx.xx.1.x IP Mask :
Link Detected: yes Mode : Auto disabled, Full, 1000 Mbits/s
Duplicate IP : no

Primary : Secondary :    ( I JUST WANT TO CHANGE THESE)
Options : timeout:5 attempts:2
Domain :
Gateway : 1xx.xx.1.1 on Ethernet 0


Do i only need to restart Tomcat for this? 





Just found a customer that never set it on some subs and was doing research but yes it will interfer with licensing per cisco documentation below.  I believe this is only 8.x but not 100%.


Usage Guidelines

If Cisco Unified Communications Manager or Cisco Unity Connection is installed on VMware, the set network dns primary command changes the calculated value of the license MAC and invalidates the Unified CM or Connection license.

For more information about replacement Unified CM licenses, see the section “Obtaining Rehosted Licenses When You Change License MAC Parameters” in the Installing Cisco Unified Communications Manager Release 8.0(2) guide at

For information about replacement Connection licenses, see the “Managing Licenses in Cisco Unity Connection” chapter of the System Administration Guide for Cisco Unity Connection at .

Hi Adam,


do I need to remove and add PLM instance instance and reboot cluster for this DNS IP address change?

I am using CUCM 10.5 version 


Primary : Secondary :    ( I JUST WANT TO CHANGE THESE)
Options : timeout:5 attempts:2
Domain :
Gateway : 1xx.xx.1.1 on Ethernet 0"



Please confirm!!!




You only need to add/remove the PLM instance if the IP Address and/or hostname changed on the server it is referencing.

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