2 VLANs Sharing Internet Over WAN Interface

The image shows the proposed new network topology.

Until today all four ports on the TP-Link Archer C7 in Basement Office 1 were on the default OpenWRT LAN, and isolated from the upstream Merku network via NAT.

Specifically, the Mercku Network is 192.168.127.x and the TP-Link network is 192.168.2.x.

As depicted in the image, I'd like to use port 4 (green henceforth) on the C7 to feed Basement Office 2 as an extension of the Mercku M2 network (in the 192.168.127.x range). I'd like ports 1, 2 and 3 (yellow) to remain behind NAT in the 192.168.2.x range and isolated from green.

To this end I created a new VLAN (3) and tagged as per the screenshot below only because it mimics how the other LAN is tagged. In truth have essentially no idea what I'm doing. I don't understand why there are two CPUs or much of anything else to do with VLANs.

I created a new interface called Basement

I was hoping this would be enough to get things moving but I'm still getting no IP on the laptop I've plugged into green for testing. Clearly this needs tweaking.

What have I missed? (Probably lots of stuff).

If you want a LAN port connected to the upstream device then you should tag it the same way as the wan port, ie vlan 2. And you don't need a new interface. (You already have got WAN obviously.)

Okay, I'll try that but I'm unclear: if VLAN 1 is the LAN my computers connect to (and they have internet) then why wouldn't I tag VLAN3 the same way?
As I implied earlier I have a distinctly underdeveloped intuition on these matters.

Okay, I'll delete that.
Shows what I know about VLANs or Interfaces or anything else. :man_facepalming:
Learning new stuff is cool but being ignorant suuuuucks.

I tried what mikma suggested but still don't have a connection on green.
I've revised my original post for (what I hope is) clarity.

It's possible if you want to configure another LAN (LAN2?) But I thought you wanted to connect the port to the upstream router, ie to the WAN of the OpenWrt device which is VLAN 2.


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I want green to be on the Mercku M2 LAN (192.168.167.x) if possible, and not on the yellow LAN (192.168.2.x).

Just move port 4 from vlan1 to vlan2 and packets will be hardware switched to the wan port thus going directly upstream. You don't have to change anything else.

Watch the status change as you plug and unplug cables--- make sure you're actually plugged into the correct port as sometimes the physical port numbers don't match the software numbers.

I've colored all the ports in the diagram to reflect their desired LAN affiliation.

Ah, okay, I'll try that now.

Yes, I took note of which port is which.

That did it, thank you!
I'm don't understand exactly why it works but it seems to be doing so in spite of this, and that will do for now. :slight_smile:

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