change of DNS in CUCM

[iptuser55]

I`m due to change the DNS address in CUCM 5 to point to another DNS server. Is there any issues with this.A couple of questions

1. Potentially I think the CUCM will lose connection to the GW while we do the change

2. I do it on all CUCM servers in the cluster ?

3. CLI Commend SET NETWORK DNS PRIMARY....

Has anyone done this and is my thinking correct

thanks

[Ayodeji Okanlawon]

Hi,

1.If you are using H.323 gateway, the Callmanager does not rely on hostname for this to work, it uses IP address, so you wont be affected.

2. Yes do it on all CCM servers in the cluster

3. Yes that is the command

[iptuser55]

I`m using MGCP so I pursume I lose connection during the change?

[Ayodeji Okanlawon]

no, cause mgcp doesn't rely on DNS.. when a gw registers with ccm.. it send its hostname and domain in the mgcp setup.. so dns isn't used.

[iptuser55]

We had to add the hostname of the GW gwname.uk.x.x. in DNS as only then could you ping the gw using the host name from eth ping option in CUCM

[Ayodeji Okanlawon]

Yes, I know. But have you tried without adding the host name to see if the gateway registers?

The question is does CCM uses ICMP to accept gateway registration with MGCP?

This is required in CCM4, but with CCM6 I am not sure it is.