Hi
It is possible but had to be tested.
You can go to Configuration > Templates > Feature Templates.
Add Templace ==> Select your device.
Once you select your device, the Templates dashboard will show up.
Scroll down to "Cisco DHCP server"
Give a template name.
Add Pool, Excluded Address and lease.
In DHCP option (Here is the point to be tested). IP phone requires option 150.
In Advanced, you can add the Default Gateway , which will be the router if this router is the only Layer 3. If the switch where the IP phone is connected also do Layer 3 function, you can add it here but then you need to use "ip helper address" on the switch.
Save the template and apply to your router.
From CLI: (This is just an example, edit accordingly)
Device# config-transaction
Device(dhcp-config)# ip dhcp pool DHCP-POOL
Device(dhcp-config)# network 10.1.1.1 255.255.255.0
Device(dhcp-config)# default-router 10.1.1.2
Device(dhcp-config)# dns-server 172.16.0.1
Device(dhcp-config)# domain-name DHCP-DOMAIN
Device(dhcp-config)# exit
Device(config)ip dhcp excluded-address 10.1.1.2 10.1.1.10
About the vlan question. The DHCP server does not care about VLAN, no difference if the DHCP server is a router or other device.
What the DHCP server does is, after receive a DHCP request, it replies with IP address, gateway,etc.
The vlan where the device is connected, must have a layer 3 configuration somewhere, either on the switch itself or in the router, but will be from there (layer 3 interface) that the DHCP address will be sent.
I imagine you topology as:
Router
|
Switch
|
IPphone
|
PC
So, it is up to you if the L3 will be on the switch or router. But, the configuration on the switch port must follow the standard config which inclusde the "voice vlan" command and this voice vlan need to have a L3 somewhere, the same way as data vlan.
If the Layer 3 will be on the router, then, router and switch must have trunk with vlans allowed. Just like any "router on a stick" topology.
