Raspberry pi to ISP Router on different subnet (Question) [Solved]

Hey, I'm new to all this tech stuff, so sorry if this sounds dumb. Can devices connected to the Raspberry Pi with OpenWrt communicate with the ISP router that's connected to the Raspberry Pi via LAN?

Say for example like raspberry pi is with connected user devices after that and the ISP router is which is before that and with other devices connected on it

So can user devices communicate with ISP router and user devices on it
No right?

It becomes something like a VLAN right?

Also is firewall only applicable through Raspberry Pi with Openwrt and ISP router has no play on that anymore
Yes right?

This may be possible, but it entirely depends on the topology and also the capabilities of your main ISP router.

  • Please draw a diagram of how things are connected (a photo of a sketch on paper is fine).
  • What is the purpose of the Pi running OpenWrt in your network (what do you want to use it for, what are you goals)?
  • Does your ISP router support static routes? (depending on the answers above, this may or may not be all that important, but I'm asking now so we have a complete picture).

Hi psherman thanks for the reply

I tried my best to draw things out sometimes written communication just cant better audio communication if only we could upload audios to forum post and to any forum platforms anywhere and I dont only mean here on Openwrt but the entire web and if voice is concern with the ability to alter the voice oneday maybe oneday but not today lol

Now back to the original topic: :slight_smile:

Diagram uploaded

Currently the Raspberry PI 4 with Openwrt is used as a portable VPN with OpenVPN installed and with two Wifi cards one internally and one on the USB

but is only used on the Wifi of the ISP router I would like to add it to also LAN whenever I want or just leave it dedicated on the ISP router from what I found to be obvious is no Guest mode in LAN or any routers found anywhere except ones with VLAN equipped
I want devices to not communicate with each other be it LAN also be it WIFI but WIFI can be guest mode so then only on LAN I guess

The thing is I cant switch the router or buy a new one as its the Landlords Router and cant be changed but can be altered in the settings the landlords a one loopy individual if you ask me but anyhow back to the original topic oh also the router has the ability to turn off DHCP or even changed its settings is this what you meant by being static?

What I'd like achieve ultimately is to use it for separation with all LAN devices on Router without any of them being able to see or even communicate with eachother be it LAN and also be it WIFI

I think my current RPI setup would work if I buy a ethernet USB 3.0 adapter which would top at 500mb Really good IMO of the 1Gbp ethernet port of ISP router
right now RPI is on WIFI so LAN slot is empty and not being used so why not use it as a Guest LAN mode VLAN mode or whatever you wanna call it

any suggestion?

What devices should not be able to communicate with each other? Can you be more specific? For example, if the goal is to not have any devices talk to each other, that is different than just having the devices that are connected to the Pi not able to talk to the devices on the ISP router and vice versa.

Can you clarify this... is your desire to use the ethernet port instead of wifi for connecting the Pi to the ISP router? Or do you want to use the ethernet port for only your devices that are connecting to the pi?

no. I was talking about a different function, but it is clear you cannot make changes to the ISP router (landlord), and it is also apparent that you don't want devices to communicate, so the static routes will not be necessary anyway.

Again, please clarify if this is just with the upstream (ISP router), or if your intent is to isolate all devices. Further, it's important to know if this will include devices on ethernet.

Sorry i'm finding it really hard to explain I will try my best to make it easier
lets forget about Wifi as this can be on guest mode with the original ISP router so all is good on that part

Now as for Lan well make it something like this ISP Router > RPI Openwrt with USB 3.0 Ethernet > LAN devices connected to RPI Isolate

Each ISP routers Ethernet port will have its own RPI with Openwrt and USB 3,0 Ethernet adapter with devices connected to it

So No other devices on ISP router ethernet port except the RPI with Openwrt and USB 3.0 Ethernet port and devices below that

I know this will be expensive but I really have no other way to accomplish this LAN Isolation
I've drew a better example

So would real Isolation be Possible?

If you want to isolate all Ethernet Devices from each other, the simple solution is to get a managed switch that supports port isolation. Although I do not like the TP-Link TL-SG1xxe devices, they offer something called Multi Tenant Unit (MTU, not to be confused with maximum transmission unit). It effectively isolates all ports from each other except for the connection to the upstream (so that internet connectivity works).

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Perfect thank you so much only the internet would be suitable on those devices I live in a flat we all share internet everyone will be happy with this idea with full privacy for everyone

That is precisely what that switch is targeted to serve... basically a super easy and inexpensive method to get isolated ports perfect for that application. VLANs can do the same thing, but this is far easier (it's designed for the non-tech based landlord who provides internet to their tenants).

If your problem is solved, please consider marking this topic as [Solved]. See How to mark a topic as [Solved] for a short how-to.
Thanks! :slight_smile:

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