Hi JT,
I did a write-up once for the SG300, it might help:
If you run the SG300 in L3 mode then it can route between the VLANs and you can use it as a DHCP server. There are a couple of things you have to do if you want your hosts in the different VLANs to use the router for Internet access.
First you’ll need another subnet between the SG300/router so that they can reach each other.
Once you can ping between the SG300/router, you’ll need three more things:
- The SG300 requires a default route pointing to the router, without it the SG300 has no idea where to forward traffic destined to the Internet.
- The router requires static routes for all your 192.168.xx.x/24 networks or it will have no idea how to reach these networks.
- The router has to NAT all 192.168.xx.x/24 networks.
In the link above I configured a trunk between the router/SG300 but that’s only needed if you want to use the router for all routing / DHCP server.
Hope this helps!
Rene