I have a question towards the bottom here...but I wanted to give my background and system setup before I ask it:
I am new to this type of router/switching setup scenarios. I am pretty well versed in networking in general and have a basic understanding of routers, level 2 and level 3 switches, etc. and a high level of enthusiasm to learn more! Any tips, help, answers to my question or "don't do what you are planning because x,y,z", etc. are very much appreciated.
I have an ERPOE-5. I got it working as SOHO with the 2lan2 wizard. Got my UniFi AC Pro connected and everything up and running fine (eth0 is WAN to cable modem and eth1 to eth4 are all bridged with a DHCP server running on the ERPOE-5 at 192.168.1.1 and everything on the lan works fine.
I have a level 3 CISCO SG300 switch and a level 2 CISCO SG200 switch. Now I want to go ahead and configure my vlans. I dont want to bridge the ports on the router not only because of the performance hit mainly because I want to learn about routing between subnets, firewalls, etc.
I plan to have 3 different SSID's on the WLAN each on a seperate VLAN connected to eth4. I plan to have one dumb switch (netgear 8 port switch) connected to eth3 to allow internet access to a couple of wired devices that simply need internet access (like Satellite Dish system). I plan to have eth2 connected directly to my Synology NAS to allow it to have direct internet access from one of its ports and use the other port to connect to my main LAN.
What I am planning is this:
Reset the ERPOE to remove the bridge. Configure each port as its own subnet (leaving eth0 as WAN of course). Run my main lan on 192.168.1.0/24 on eth1 and connect my level 3 SG300 via port 1 to it (eth1), and setup the other ports on the router as I have stated above. The SG200 level 2 switch is connected to port 2 on the SG300. Both port 1 and port 2 on the SG300 will be trunks and port 1 on the SG200 will be a trunk.
I have a plan, watched a ton of videos and read a boatload of information and I THINK I have an understanding of how it works.
Now for the question:
I was hoping to just have the level 3 switch take care of routing between VLANs on itself (so traffic stays local without going up to the router if it doesnt have to) and let the router route between VLAN's on itself. This seems fairly straightforward to setup but where I am running into trouble with my planning is this:
Lets assume I have a PC-5 on SG300 port 5, set as VLAN 5 (access port). I want to communicate with PC-6 on VLAN 6 on port 6 of the SG300. Assuming both were set with static IP's, the proper gateway address to the VLAN interface on the swtich and the gateway was set on the SG300 switch, this should be no problem. The switch will route properly. However, where I get into trouble is that I don't want static IP addresses and gateways, I want to use DHCP.
I know I can simply create a DHCP server on the SG300 switch to serve up addresses to the VLAN and this will work fine then. But what I don't understand is what happens to the devices up off eth4 of the Router that are on the same VLAN as PC-5 (VLAN 5)? Does it then have to go to the DHCP server on the switch to get an address and then use that switch as its default gateway? I was hoping, for example, a client on wireless would simply go directly from eth4 to eth0 to get to the internet, but I don't see how to make that happen in this scenario.
Any help would be appreciated. Also, any recommendations as to what I should do differently would be appreciated. I know that this is overkill for a home network, but I have the gear and want to learn...so I am trying to make the best of it.
Thanks.
Eric