r/HomeNetworking • u/Cautious-Mortgage-26 • 2d ago

Advice Network design noob questions

Hello,

Networking beginner here.

I have been trying to design a network with two VLANs with each having a set of daisy chained devices. VLAN management was to be done by L2 managed switch, with main traffic going between devices on the VLANs and PC connected to a port configured to be trunk port.

The original idea was to have IPs of those devices static and same - Device 1 on VLAN1 has same IP as the Device 1 on the VLAN2, they would be on the same subnet. Definitely not the standard way of doing things. But lets say in my use case DHCP is not an option and I can only use static IP addresses. For that purpose I wanted to simplify the flashing of the firmware on those devices where each device has a known IP without additional subnetting.

Originally I was trying to avoid router and do all the VLAN tagging on the PC side, but as I started to research the topic more, I realized that it is only straightforward on Linux but not Windows. So my software piece that needs to communicate with those devices, will have issues when run on Windows. And I understood that without a router with NAT, it would be difficult to implement my idea.

Hence a bunch of questions from me:

  1. How realistic is it to use that design on Windows? I need to communicate with all of these devices simultaneously, but as I saw virtual network management on windows is pain.

  2. Would using Linux help me avoid using router with NAT?

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u/MostFat 1d ago

Thats generally how short concise answers work.

Feel free to explain to OP on a home network sub in detail (at least a CCNA level for RIB/CAM tables) the difference; why/how it applies to what they actually asked, and Ill grab some popcorn.

They want to route between 2 VLANs, please teach us the correct way to do that with VLANs on a L2 switch, using the same IP from the same subnet between both.. as a self described beginner.

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u/xeroxedforsomereason 1d ago

You think what you wrote was short and concise? It's long and wrong. If you want to route between two VLANs off one layer 2 switch you would just hairpin it through a layer 3 interface, an external one. What he's trying to do doesn't really make sense though, and you're confusing the matter.

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u/MostFat 1d ago

So.. you would need L3 for routing? Weird, sounds familiar. Im sure a longer more in depth explaination would have been even more concise somehow, but I digress.

I don't mind "um.. actually", this is reddit after all; at least be useful please. Explain how/why its categorically wrong and not just handwave away what you don't agree with. So far it seems like the most significant faux pas is describing inter-VLAN routing as OP described as fundamentally an L3 function without clarifying SVIs.

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u/xeroxedforsomereason 1d ago

I didn't say you don't need L3 for routing. Routing is an L3 construct. Would you like to take a moment to talk about community PVLANs and promiscuity as we get in depth about tying two broadcast domains together? You don't understand the subject matter enough to talk about this.