SG300-10 and VLANs with Windows DHCP Server and Sonicwall

Hi all,

First am new to this in terms of VLAN’s etc

I have a SG300-10 I want to create 4 VLAN’s on it - this is to be our master switch in L3

VLAN 10 - IP
VLAN 20 - IP
VLAN 30 - IP
VLAN 40 - IP

I can create these the problems am having is that connected to all this I need our windows dhcp to give out addresses to all these VLAN’s and also our internet is via a sonicwall firewall device, am unclear on how to get this to work if anyone can help with this or point me in a direction I should be looking at



Hello Gaz

In order for one DHCP server to provide IP addresses for multiple subnets, it is necessary to enable DHCP relay. This is a setting that relays all DHCP requests to an “out of subnet” DHCP server. On Cisco devices with a CLI, this is usually configured on the SVI as “ip helper address X.X.X.X” where X.X.X.X is the IP address of the DHCP server. For more information on this command on the SG300, take a look at pages 763 in this command line reference document.

If you are working with the web interface, it should be a setting under something like IP Configuration >> DHCP >> Interface Settings and enable the DHCP relay service for the desired VLANs. I don’t have such an interface handy, so you might need to search a bit more for that one.

I hope this has been helpful!


Hi Laz,

Sorry for the late reply, thanks for you help managed to sort it out and get it all working