Unity Connection 12.5 DNS setting changes.

[john.corbett28]

HI There,  

hoping someone has done this before and can help me out, as i am struggling to find any official Cisco documentation to help. 

We're having to change all of the DNS server IP addresses in our CUCM cluster, 

I have the process for CUCM and UCCX nailed down, I just also need to change the DNS IP addresses on CUC too. 

when I change the Primary and Secondary DNS  addresses in CUCM I have to restart the server following the change, 

when I do the same on UCCX I simply have to restart a service,

changing the Primary and secondary DNS server on Unity Connection is the same process as on CUCM , however does anyone know - 

if a reload of each server is required once i make the change ? 

thanks 

in advance all. 

[Roger Kallberg]

From what I can recall from doing this on CM and CUC you don’t need to restart anything. It will automatically do a quick restart of the network services on the node, but it’s not really affecting any services.

[john.corbett28]

Hi Roger - thanks for your reply, 

the Documentation for CUCM12.5 specifically states the server has to be restarted following a change in the Primary/ Secondary DNS server. 

I just can't find anything relating to making the same change on CUC, I guess as they run on the same architecture a restart would be required. just seems odd that there is nothing out there ( that i can find) advising the correct procedure to make the change.  

Thanks 

John 

[Roger Kallberg]

Can you please link to that document? As I wrote I have never done any restart of anything when I've done a change of primary or secondary DNS servers in either CM or CUC. It just flips the networking service quickly. This is also discussed in this old post in the community. [CUCM] Change DNS server IP 

[john.corbett28 · Accepted solution]

Hi Roger -  I have just received a response from TAC regarding this one  - and they pointed me to a document I had not seen full link below. 

changing these IP addresses does require a reload on CUCM,IM&P and CUC. 

Command Line Interface Reference Guide for Cisco Unified Communications Solutions, Release 12.5(1)SU1 - Set Commands [Cisco Unified Communications Manager (CallManager)] - Cisco

[Roger Kallberg]

Interesting, I can tell you from my own experience that there is no need to actually do the restart as stated in documentation. We have done this a number of times when we have had issues with one or both of the DNS servers at a specific DC and we have not done any restart of any nodes or services and have not experienced any downside of that.