Finally getting around to breaking up our flat network into some VLANs and have a question on what (if anything) I need to do to allow clients to use our router to access the Internet.
Current config is a flat network, every device is on the same subnet (10.100.0.0/16), and every client has our router setup as the default gateway.
Proposed is to implement VLANs, give each VLAN it’s own subnet (172.16.0.0/24, 172.16.1.0/24, etc), and use our core Layer 3 switch to route traffic between the VLANs. Clients would use the corresponding VLAN IP of the core switch as their gateway.
Since we have a fairly large network we plan on implementing the VLANs gradually, which means keeping the old 10.100.0.0/16 around until all VLANs and IP changes are done. Do we need to add a something on the router or another route on the core switch?