CUCM 10 / Presence 10 - DNS Client

[Tibor Marchyn]

Hello,

We have historically always disabled DNS client in CUCM as we used it from version 4 up to current version 10. Now I have installed Presence server adn disable DNS client also. But I have realized, how it can communicate with external companies in trust if DNS client is turned off?

I would like to enable DNS client for CUCM and Presence... Is only way to enable it, backup CUCM Published+Subcriber and Presence, reinstall cisco unified OS and enable DNS client in setup, then restore all systems from backup?

Thanks           

[Chris Deren]

You can easily enable it from CLI.

Chris

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[Tibor Marchyn]

But for example in Finesse I had to reinstall whole machine to fully enable DNS Client. If I just did it in CLI, it didn't work.

[Jonathan Schulenberg]

You must have hit a bug or something unique to that product. Enabling DNS isn't a big deal on most products as long as you have the records for the cluster nodes correct. You need both an A and a single PTR record (be careful to delete any duplicates) that correctly resolve the server's FQDN. Screw that bit up and you'll likely experience database replication issues; otherwise, you should be fine.

PS- If you're going to do federation, don't forget to think about what domain the IM&P cluster is in. You'll want it to be your public DNS namespace and not a fictional internal namespace. Example: cisco.com instead of cisco.local. This is because XMPP typically uses TLS and the handshake will fail if the FQDN contacted from the outside doesn't match the details of the certificate.

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