Cisco CUCM using CentOS 7 DNS BIND

DNS settings on CUCM v8.6

One of the main reasons to have a local DNS server in our LAB is to be able to configure it on the Cisco Collaboration servers CUCM, UCCX, etc.

DNS is not mandatory for CUCM v8.6

DNS is not mandatory on Cisco Call Manager v8.6, if you configured DNS when installing CUCM then you will be able to see the IP addresses assigned to DNS both, via the GUI and also using the CLI.

Checking DNS on CUCM 8.6 via GUI

CUCM v8.6 – OS Administration – Show Network details
CUCM v8.6 – OS Administration – DNS details

Ping DNS server from CUCM GUI

Services Ping
DNS server is reachable through Ping

Checking DNS on CUCM 8.6 via CLI

You can use the following CLI command to check that DNS is working properly.

utils network host
Checking DNS from the CLI

Another useful CLI command available on CUCM v8.6 is the “utils diagnose test“, this command also check Tomcat, NTP, DNS forward and reverse, HDDs and several more infraestructure related parameter is the perfect indicator of a healthy system and proper connectivity.

utils diagnose test
CUCM v8.6 – Utils Diagnose Test

Accessing CUCM using its Hostname

Once you’ve verified that everything is alright it is time to use the CUCM hostname on your web browser to fully test DNS, for that you must add the DNS server IP address into the Windows network adapter protocol IPv4 settings, see screenshots below.

Open network adapter properties
Go to protocol IPv4 properties
Add your DNS server IP Address
Use the CUCM hostname on your web browser
DNS is working OK

You did it! DNS is working as it should – Congratulations! Job well done!