Managed Switch or OpenWrt?

I do not have control over my router.

I want to seggregate my traffic with vlans.

Do I need to buy a managed switch or can I use an OpenWrt router?

The ISP router is a blackbox.

Will it knows my managed switch/OpenWrt router vlans?

What's the best way?

You'll need a router, to do the network segmenting (into VLANs) and do the routing between the different VLANs on L3, switches work on L2.

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ISP > OpenWrt router > switch? will that have double NAT?

Not necessarily, if your ISP router allows you to configure static routes, you can disable masquerading (NAT) on the router.

The thing is I don't have control over the ISP router...otherwise I would just use OpenWrt and be done with it.

If your OpenWrt router has enough LAN ports, you will not need the managed switch.

Devices that see the VLAN need to be configured to understand VLAN traffic so you cannot connect a VLAN trunk port directly to the ISP router.

If you segregate traffic with VLANs then you have at least 2 subnets, (one per VLAN) so for example and

It is useless to run the same subnet on multiple VLANs as all devices will still be able to talk to each other through the port connected to the ISP router.

So if you have no access to ISP router you have to get a OpenWrt router that will NAT all the subnets you want to make with VLANs into the single subnet that the ISP router understands. And an additional switch if you need more ports.

Yes this is double NAT if you cannot touch the ISP router. It should be OK for most web application use but can be an issue with some games or special applications.

Some ISPs will do the configurations on the ISP router if you ask through the customer support tickets. Most ISPs with cable in US usually have remote control access to the device.

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Can you or customer support set the ISP router in bridge mode? This should solve a lot of your problems and you can run your own (OpenWrt) router behind it.


Will that be ok for IRC, P2P games, UPnP and alike?

I will try that.

Thank you for your informative answer.

How about a L3 switch?

Bridge mode is not ideal for me.

I don't understand? Ideal would be to replace the ISP device, which in a lot of cases can't be done. The alternative to bridge mode is double NAT as mentioned by @bobafetthotmail which I would consider less ideal.

But based on "not ideal" it does suggest that you would be able to do it.

A L3 managed switch is just a switch with limited routing capabilities beyond mere switching, but the situation is still the same as with a 'normal' router. Either you can set a static route on your ISP router XOR you have to do masquerading (and end up with double-NAT).

There is one other option... use a setup similar to the dumbAP + guest network route. Your additional VLANs would still be double-NAT'd, but you would still be able to have one of the networks only behind the single NAT layer (of the ISP's router).

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any service that relies on UPnP or opening ports on the router will not work (as it requires a port forwarding in the ISP router that is not accessible).

A lot of modern applications are designed with this limit in mind, but I don't know about games or consoles, afaik they still may need you to open ports or use UPnP on the router.

That's a router, same issues.

It would be ideal if the ISP router could be put in bridge mode actually, that usually means it disables its firewall and will just "passthrough" the IP of its own WAN interface to the WAN interface of your router, so you are not doing double NAT anymore.
This is something you can ask the customer support of your ISP.

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I managed to get a netgear router working instead of my ISP.

How can I make 3 ethernet ports working with regular ethernet without vlans tags and just 1 with 1 vlan tag? it's a 5 port router.

Does this mean the netgear router is now connected to the ISP router in bridge mode, or the netgear router is connected to a modem only device, or something else?

Also, the instructions to do what you want are a little different depending on whether your netgear OpenWrt router has been converted to DSA or is still using swconfig. What model netgear router are you using, and what version of OpenWrt is installed on it?

Sorry for the delay.

It is connected to a modem only I was told.

It is a Netgear R6800 and I just installed OpenWRT [21.02.1] and left stock for now.

Your R6800 is a MT7621 device. This ramips target has been converted to DSA.

Instructions for setting up VLANs with DSA are found here:

There is also quite a bit of good information and discussion in this thread:

This information covers what you would like to do and is also good general knowledge for expanding or changing your network in the future.

Maybe I'm dumb but shouldn't be br-lan.4 if you wanted VLAN tagged traffic on the example above?

Also since I just need one port using tagged VLANs I think using one port for br-home and all others to office should suffice? is it possible to assign just one port to one and the rest to the other(home and office)?