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CB350x - VLAN and DHCP



I'm knew to CISCO hardware so please bear with me (also I'm using the GUI).

I'm trying to set up 2 VLANs
VLAN1: - voice
VLAN2: - data

VLAN1 will be connected to a BT router which will act as the DHCP server
VLAN2 will not have a seperate router

I'm looking for all phones to join VLAN1 based in OUI values and everything else to join VLAN2.

My question is - can this be acheived with this switch and if so how? I can't see a way for the switch to provide DHCP to VLAN1 and have VLAN2 use the connected router. Any thoughts?



4 Replies 4

VIP Mentor VIP Mentor
VIP Mentor


 - Use the ip helper command described in . to point to the dhcp server for the none directly connected vlan. (meaning the vlan which does not have the dhcp server in its subnet-domain).




As far as I know the CB350x series switches are routing switches and they include a DHCP server. As such, they can work with just any Internet router and provide IP addresses in any VLAN you define. You do not need to use your router for DHCP. Also with some simple planning you can use both DHCP servers. I am not familiar with voice VLANs, but I think you should be able to implement the depicted configuration.

Kris K

Jitendra Kumar
Rising star
Rising star

Martin Aleksandrov
Cisco Employee
Cisco Employee

Hi there,


The switches always have VLAN1 as a default VLAN which is used for control plane traffic (STP, VLAN trunking, etc.) which you could not use for other purposes. Please consider the following deployment scenario:


1. Create VLAN 2 as a Voice VLAN, respectively enable Telephony OUI. Please note Auto Smartport and Telephony OUI are mutually exclusive. We recommend disabling smart ports on the switch.

2. Leave VLAN 1 as a Data VLAN or add another VLAN 3 for Data VLAN

3. Use the DHCP server on the CBS350 switch and set the IP ranges for both VLANs

4. The switch port connected to the BT router must be a trunk port. 


Here is a more detailed guide on how to set up the VLANs and DHCP on the CBS350 switch and how to configure the Voice VLAN:







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