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DHCP, Vlans, Nortel phones

 
kevinadams
Occasional Contributor

DHCP, Vlans, Nortel phones

I figured out the first part of this and thought I was home free (http://csoweb4.3com.com/forum/viewmessages.cfm?Forum=9&Topic=1847) but now I find I have a different problem.  We stood up a secondary DHCP server at one of our campuses.  We then put the DHCP Relay info into each edge switch for each campus to point to that new DHCP server in addition to our first one.  This worked beautifly and I could shutdown the primary server and this server would pick up the load.  Knowing the secondary server was in the subnet with the campus it resided on, I left it's address out of that campus edge switches DHCP relay config because the 3com manuals warn about incorrect address assignment.



The problem:  We use Nortel IP phones who get DHCP on VLAN 1 and then through DHCP Option 191 (Phone Option#191) release their vlan 1 IP, move to vlan 10 and then rerequest DHCP where they are served an IP from a different scope for the voice vlan.  Since I've stood up the new DHCP server, IP phones in its subnet never get an IP on their intended subnet.  They stay in the subnet intended for vlan 1.  I don't know if they are getting their IP, releasing it and trying for vlan 10 but still being handed a vlan 1 IP, or if they are simply ignoring the PhoneOption#191 directive to move to vlan 10.  All other phones getting DHCP from this new server do so via DHCP relay and work fine.  There is no DHCP relay between these phones and the DHCP server and they get IP from the wrong scope every time.  I think it's because their requests always come from the edge switch in vlan 1.  Is there a way to make their request come from vlan 10 to the DHCP server via it's trunked port?  Can anyone help?