I have a Cisco 3560 Switch that has each port configured for a data VLAN (VLAN 10) and a voice VLAN (VLAN 2). DHCP on the Data VLAN comes from a Windows 2003 server. DHCP for the Voice VLAN comes from a Cisco PIX firewall.
Data subnet 172.17.100.x
Voice subnet 192.168.0.x
Here is a sample config from one of the ports on my Cisco 3560 switch
switchport access vlan 10
switchport trunk encapsulation dot1q
switchport mode access
switchport voice vlan 2
mls qos trust cos
The problem is that phones when booted up pull DHCP from the data vlan. to get them to pull from the Voice VLAN i have to hard code the switchport access to VLAN 2 on the port they are connected to. Once they bootup and pull the correct IP, I change the switchport access back to VLAN 10. The desktop pcs are connected to the same data cable through the phone. If I turn the Windows DHCP server off, the phones boot up and pull the correct VLAN 2 IP address just fine.
Am I missing something in my Windows DHCP scope options?