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I have a client that has a DHCP server for voice and a DHCP server for data. They have both voice and data on the same VLAN (I know, not ideal). Some of the computers are getting DHCP addresses from the voice DHCP server. Is there a way in the switch to designate the DHCP server a port uses?

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Is the DHCP server a router? Or an windows / linux DHCP server – hbrock Sep 29 '12 at 4:11
Not likely. What switch do you have? (You're better off doing it in the DHCP servers.) – David Schwartz Sep 29 '12 at 4:15
I think you need to get a basic understanding of how DHCP works. – John Gardeniers Sep 29 '12 at 5:24
Please mark an answer if one of the suggestions was useful to you. – ewwhite Oct 2 '12 at 22:49
up vote 3 down vote accepted

The right solution here is to use one DHCP server and separate the voice and data traffic...

In lieu of that, you can use a single DHCP server to serve both. In VoIP deployments, the DHCP also may hand out boot images to the phones and specify a tftp server. Check with your phone vendor to see the recommended setup with your existing data DHCP server.

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Short of providing some mechanism of VLAN separation your best option is to use a single DHCP server that allocates addresses based on the individual MAC or, better still, vendor class (i.e. MAC prefix) for your phones. As you've noticed, if there are two (authoritative) DHCP servers on a subnet then the client will take the answer of whichever answers fastest.

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