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DNS environment for a Cisco VoIP shop?

admin_2
Level 3
Level 3

Hi all...

Does a Cisco IP telephony implementation depend on DNS? Are there enterprises who have a successful Cisco VoIP implementation without it?

If not, what DNS implementations are supported?

Thanks!

4 Replies 4

Hin Lee
Cisco Employee
Cisco Employee

>>depend on DNS?

Depends on what you are referring to. If you use hostnames instead of ip addresses of callmanager, then the phones will have to be able to resolve CCM hostnames.

If you do not need external name resolution for your CCM, such as going to the voice download page on www.cisco.com, then the CCMs do not need it either.

If you are writing about Unity integration with Windows 2000 domain, then most definately you will need it.

H. M.

Callmanager and IP Phones definitely donot need a DNS for their operation, though its an option to use names instead of IP addresses. Unity requires that you integrate with Active Directory, which will require you to have DNS installed either on the local Unity machine or another Windows 2000 machine.

Sankar Nair
UC Solutions Architect
Pacific Northwest | CDW
CCIE Collaboration #17135 Emeritus

gshonting
Level 1
Level 1

DNS is not necessary for Call Manager/Phones/Gateways. I always configure my systsems to use only IP Addresses, I don't want the phones to fail bacause of a DNS problem. However, if you decide to use DNS, any DNS server will do, it is a standard (the whole internet uses it). As mentioned above, unity will need DNS in the domain, but if you have a windows domain then that is already running anyway.

Be cautious with MGCP gateways. The hostname and domain name configured on the gateways is what is sent to CCM for the Domain Name under MGCP GW. If someone chnages a router hostname, domain name down the road down comes the calls.