VLANs with DHCP on SG 200-50 switches

[newinnovations]

Hello,

I have 3 Cisco SG 200-50 switches ithat I'm using for a new set up. The 3 switches plug into a SonicWall appliance for routing and Internet access. I would like each SG switch to be a separate VLAN (ie. VLAN 10, VLAN 20, VLAN 30).

So I have my main network at the SonicWall level: 10.10.0.1

Switch A (SG 200-50) would be VLAN 10: 10.10.10.1

Switch B (SG 200-50) would be VLAN 20: 10.10.20.1

Switch C (SG 200-50) would be VLAN 30: 10.10.30.1

On my "main" network I have my email, DNS, and DHCP servers which supply the IP addresses for each VLAN. I have my DHCP server configured with 3 scopes (1 per VLAN). However I can't see a way using these switches to tell these VLANs which scope to request IP addresses from?

Am I doing this wrong or should I redesign my layout?

Thanks in advance!

[Tom Watts]

Hi Steve, this seems to depend on what the Sonicwall supports. The DHCP server and Sonicwall we will need to have the correct DHCP relay configurations. 

The SG200 switches are only layer 2 device which means they will not route VLANS. This translates in to a couple of concepts. The Sonicwall will need to support 802.1q either through sub interfaces or a trunk. If the Sonicwall does not support this then you may run 3 physical wires in to each respective VLAN from the router to the switches.

-Tom
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[bhackbarth]

Everything Tom said, and depending on what FW version your sonicwall is running, you can do 802.1q trunking. Please see this tech document: http://o-www.sonicwall.com/app/projects/file_downloader/document_lib.php?t=TN&id=49

While the SG300 switches are much more robust; (you can assign an IP interface to each VLAN and use the switch as the default gateway to reach other VLANs, another router, the internet, etc)  it looks like you'll be fine since sonicwall has been implementing this feature since at least 2008.