Cisco Call Manager

[1ceHacka]

Running CCM 4.1 (old yes I know) in a lab environment to test for patches for our "legacy" IP phone locations. Currently, we have a C 2821 router sitting out on the edge connected to the MPLS cloud and then a catalyst 3560. This 3560 holds CCM 4.1 and some other devices. This is a lab environment, keep that in mind. Currently, IP phones registered with the CM are pulling having their DHCP requests answered by the CM. This is ONLY because it is on the same subnet and is answering before the router can answer. I am looking to setup IP Helper-address on the 2821 for the phones only. I want the router to answer all DHCP requests from devices, except for phones; CM will give them their address. This is only for testing to see if it works correctly. Now, it does work, but only because the CM is faster than the router in response. If the CM were to be on a different subnet, the router would start answering (I assume). Thanks in advance if anyone has anything to add.

 

[rathsach]

You'll have to have only one dhcp server pr. subnet if you want to control it as you wish..

I don't know if you can use it for anything, but you can block bootp packets (dhcp requests) in a Cisco access-list.. Maybe that's useful to you..

 

[Jamsan]

Move the CM to a different subnet and use DHCP vendor options on the router to point phone requests to the CM, and the router serving the rest o the devices.

 

[m1ldslide1]

Originally posted by: Jamsan
Move the CM to a different subnet and use DHCP vendor options on the router to point phone requests to the CM, and the router serving the rest o the devices.

This. One subnet / VLAN for voice traffic and another for workstations/printers. That's the only real way you're going to control who gets what DHCP server, unless you want to start typing out phone MAC addresses for some kind of funky filter.