DNS configuration on live system

[adnanhassan1]

Hi Guys,

we are running CUCM 9.1.2 and CCX 9.1.2 but no DNS/FQDN configured on both servers (only using IP addresses). Now I have to put DNS entries in DNS server for couple of reasons:

1) self assigned SSL certificates has been expired on both CUCM and CCX, So I am looking to renew new SSL certificates properly with DNS/FQDN etc

2) CUCM and CCX upgrade is due end of the year so might need DNS configured for new CUCM and      CCX.

My question is:

If i make DNS entries only to get SSL certificates sorted and do not change any configuration in CUCM and CCX until whole system upgrade. Will this effect on production system?

Thanks

Adnan

[Jaime Valencia]

Adding / changing / removing any of the DNS configuration requires the NIC to be restarted and that takes a few seconds, you want to do this when there is no traffic in your system.

[adnanhassan1]

whats the best way to restart NIC?

Also does DNS entries impact on CCX agent and IP Phones?

Thanks

[Jaime Valencia]

The procedure will do it, you'll get the warning about the restart before you complete it.

[Deepak Rawat]

Adding DNS and Domain Name information on UCCX will change the License MAC. Hence capture the current License MAC by issuing show status command from UCCX CLI beofre making any changes. Once the change is done capture the new License MAC again and provide both the old and new one to Cisco Licensing Team so that they can rehost the license files. You will get 30 days to upload the rehosted license file on UCCX, also when you will add the Domain Name information on CCX system will go for an automatic reboot so make sure you are doing this in after hours.

Regards
Deepak
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[adnanhassan1]

Hi Deepak - Thanks for replying detailed answer. But as I mentioned I am just making entries in DNS server. I have no plan to change anything in CM and CCX at this stage. 

So just making entries in DNS server will effect on Cisco world?

[Deepak Rawat]

Till the time you do not make changes to UCCX/CM there will be no impact. Just adding the entries on DNS server will have no impact on CM/UCCX side whatsoever.

Regards

Deepak

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[adnanhassan1]

Perfect!! Thanks 

Lastly - Have you got any document or steps and precautions which i need to consider for DNS configuration on CM and CCX by any chance?

[Mohit Grover]

FYI

 How to change the domain name in UCCX:

 Please change the uccx fqdn in DNS server to reflect the new domain name

 for both nodes. Make sure both forward and reverse dns lookup is working

 correctly.

 On the UCCX nodes (both pub and sub), please use the below command.

 admin:set network domain <domain-name

 The following activities have to be preformed after the domain name change:

 -          Changing domain name would require reboot of servers (publisher

 then subscriber)and will regenerate all UCCX certificates including any

 third part signed certificate.

 -          After the server reboot run the command "show network eth0

 detail" to check if the new domain name is updated correctly.

 -          Run the command on UCCX publisher "utils dbreplication

 runtimestate" after both nodes have rebooted and all services have come up

 to check if the replication looks good.

 -          Run the command "utils diagnose test" and make sure all test

 are passed.

 Domain name change will not affect your existing licenses.

 The Unified CCX licenses are based on a string called the license MAC,

 which is different from the physical MAC address of a system. License MAC

 is dependent on the system parameters. A modification to any of the

 parameters can change license MAC, thereby invalidating current License

 files. The following are the parameters on which the validity of a license

 MAC depends:

*   Time zone

*   NTP server 1 (or none)

*   NIC speed (or auto)

*   Hostname

*   IP Address

*   IP Mask

*   Gateway Address

*   Primary DNS IP address

*   SMTP server

*   Certificate Information (Organization, Unit, Location, State,

 Country)

 You can check your license MAC before and after the domain-name change

 with the 'show status' command