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Simon Battye

Mobile Remote Access - Single DNS Server Query


I have a design perdicatment for deploying MRA due to a clients existing DNS setup. The client has a single DNS server that servies both internal and external DNS queries for a single domain, the UC domain being a sub-domain of this.

So the problem i have, is that the Cisco-UDS SRV is configured and is allowing internal users to register their Jabber clients as normal but as soon as these clients move to an external network they still believe they can resolve the Cisco-UDS record as its available on the same DNS server, resulting in a failed registration attempt to an internal CUCM server from outside the network.

If the Collab-Edge SRV record is configured to resolve against Expressway-Edge, it's basically never used as the client allways sees the Cisco-UDS SRV first and attempts to use this based on the native client behaviour

I've thought about the voice services domain setting in Jabber-config.xml and also using two seperate domains but i can't see this working either as the problem is actually with the same DNS server being available both internally and externally,i guess the current DNS deployment is "single domain, not split-brain" whereas the voice services domain would come into play in a "seperate domain" design.

If anyone has come across this scenario before or knows of a workable solution, that would be great!

Thanks, Simon



Unfortunately this will never work. As long as the client can resolve the cisco-uds query it will not query the collab-edge record.

There is no work around for this. You will have to eductae the customer on how the solution works and how their current DNS implementation cant work with it.

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