CUCM 12.5.x DNS failed

[Juraj Papic]

Hi all,

I'm installing a new cucm 12.5.x and I'm stuck in the DNS lookup install I did all the checks and from different servers and dns are working as expected. 

Thanks. 

[jason-mcgee]

Only thing it could be is a misspelling or an incorrect ip address either in CUCM or the DNS servers assuming the CUCM has access to them. If it doesn't then you need to check on VMware to make sure you are on the correct VLAN and/or make sure it is not isolated and connected.  

Good Luck.

[Juraj Papic]

Hello jason-mcgee.

I installed a linux vm in the same ucs, with the same Ip range and vlan , and the linux is working with no issue is resolving dns with no issue. 

Thanks. 

[Jaime Valencia]

Did you check forward and reverse lookup??

The error is specific to a PTR record not being found.

[jmeersma]

That was exactly it. A stale record in Reverse Zone. Thanks. 

[Chris Deren]

Check if you can ping the CUCM server from the DNS server, at this point it is already on the network.

As suggested do forward and reverse lookup of the CUCM from your Linux server you installed, make sure you do it more than once as if there are duplicate entries depending on DNS setup it may round robin and wrong record can be returned.  I have seen it many times, and it's always either DNS record incorrectly defined or your ESXi networking.