Using old router to route and create a subnet.

[#1]

I currently have an old BT hub set up as a wireless access point, and to provide some additional Ethernet sockets.

I am currently setting up a Home Assistant server with connected IOT devices, to enhance security ideally this should sit on its own subnet, is there a way to do this using a spare router - the primary router is a the PlusNet Hub Two router, and I have a spare Hub One.

As an aside, my current setup Hub Two > BT Hub, I presume anything sitting behind the BT hub will have the basic protections provided by that hub, ie only outward traffic allowed, all inward traffic blocked, unless ports are opened.

Thoughts Appreciated, thanks.

[#2]

Hi @1R27cD5n 

I am currently setting up a Home Assistant server with connected IOT devices, to enhance security ideally this should sit on its own subnet, is there a way to do this using a spare router - the primary router is a the PlusNet Hub Two router, and I have a spare Hub One.

Although the Hub One has a WAN port it's only use is to be connected to a modem using PPPoE, this Hub does not have the ability to setup routes to outside networks you'd need to use something else.

As an aside, my current setup Hub Two > BT Hub, I presume anything sitting behind the BT hub will have the basic protections provided by that hub, ie only outward traffic allowed, all inward traffic blocked, unless ports are opened.

How is the BT Hub configured? DHCP turned off with a LAN connection to the Hub Two? If so it will be the Hub two firewall protecting your network. The BT Hub firewall is between the LAN and outbound connection via the inbuilt modem DSL port or the WAN.

Hope this makes sense?

[#3]

I note this post:

https://community.plus.net/t5/My-Router/Using-2nd-Router-as-a-Guest-Network/td-p/1963281

Which suggests its not possible.

This post:
https://superuser.com/questions/1350877/how-to-configure-router-and-devices-for-subnetting

It suggests you need an Enterprise Router.

It also suggested flashing a router, can you flash a Plusnet Router with OpenWrt ??
I opened the Open WRT supported devices csv dump file, I know how to format csv's in Excel, and tried to, but it still looked unintelligable.
I tried searching it for 'plusnet', but nothing came up.

Any thoughts appreciated.

[#4]

See link https://openwrt.org/toh/bt/homehub_v5a a Hub One is a BT hub v5a with plusnet firmware

Some third party routers offer IoT support so maybe a search is in order TP-Link devices are well considered.

[#5]

Hi,

Yes think it makes sense, I have seen comments about the 'WAN' port on the routers, although I need to understand more about what and how and why that exists, I am on fiibre at one property, so the internet connection goes through that on the hub two, and I have an ADSL Adapter and RJ11 connection at the other property (so the WAN is available there).

I setup the BT Hub frmo a post on here, yes I think BT Hubs DHCP is off, with Lan cable connection, the Hub has a fixed IP, although on the same network. ie 192.168.1.x and 192.168.1.x.

[#6]

The Hub One and Two supports both xDSL (DSL port) and Full Fibre (WAN port) PPPoE connections, hence both ports are available for either.

The Hub One has a low specification so it's not used for Full Fibre

Hopefully our posts have caught now!

HTH

[#7]

@Dan_the_Van 

Thanks for the link, handy, better than decrypting their CSV.

I've studied flasing devices with Tasmota, so looks similar process - some soldering, and flashing devices required etc etc.

Without diving in first, could a flashed BT (plusnet) hub act as a router to route traffic between different networks ?

I need to go off and understand more about how an 'enterprise' router can do this, there must be some security mechanisms in place, otherwise you could just hop between networks I will assume.

[#8]

We're one step out LOL ...

Thanks for the info on the broadband ports, hopefully the OpenWRT Devices page for the BT hub will do some explaning, people that pick these apart I find get right into the detail ... its a gift !

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@1R27cD5n wrote:

@Dan_the_Van 

Thanks for the link, handy, better than decrypting their CSV.

I've studied flasing devices with Tasmota, so looks similar process - some soldering, and flashing devices required etc etc.

Without diving in first, could a flashed BT (plusnet) hub act as a router to route traffic between different networks ?

I need to go off and understand more about how an 'enterprise' router can do this, there must be some security mechanisms in place, otherwise you could just hop between networks I will assume.

---

[#9]

What platform is the Home Assist Server built on? I'm wondering if a second network interface could be used, so you could then route across the server, with the spare Hub One being used as a wireless access point. There would need to be a DHCP server to assign devices IP Address, DNS and default gateway as many IoT devices only use DHCP.

[#10]

Its a Raspberry Pi5 8gb with 500g SSD, so reasonable capable, but only one ethernet port.

I've not had a chance to look at the OpenWRT FW change yet, but I guess this comes down to the lack of 'management' capabilities betwen the WAN and LAN ports, I see a managed switch would allow for two networks within my LAN, is a routing table used to direct traffic between the two ?

Any idea what is currently stopping the WAN and LAN ports being managed, out of the box they routing traffic from Plusnet across to my LAN, is the WAN configured just to work with a range of Plusnet public IPs ?,

[#11]

Don't forget the raspberry pi has a wireless interface, could this be setup as a wireless access point? I have done so in the past or consider using a USB ethernet adapter. I'd do some research on the subject. There are many projects for the raspberry pi.

The Hub One and Two WAN is only for connections to a DSL modem or ONT which can be seen as a fibre modem, TCP/IP stack does not exist.

I have a TP-Link Archer AX53, the WAN port can be set to use a Static or Dynamic IP or PPPoE as stated this feature does not exist on plusnet Hubs it PPPoE only.

To segment your LAN look into VLAN, you would need a managed switch for this or maybe a router that has this feature built in.

[#12]

Thanks for advising why the WAN port cannot be used, no TCP stack,  - but a router that has this 'management' facility is required.

Good point with the WiFi point, forgeting that.

Is there a way to create a VLAN off each Rasp Pi port in Linux, ie the Wireless 192.168.1.10 and Ethernet 192.168.2.10.

I have a HP ProCurve Switch spare, I could use, huge great thing, who's fans roar, and belts out lots of heat and uses Watts of energy no doubt. Think that has some quite extensive management software.

[#13]

@1R27cD5n 

Is there a way to create a VLAN off each Rasp Pi port in Linux, ie the Wireless 192.168.1.10 and Ethernet 192.168.2.10.

I've had a pi3 with ethernet being on 192.168.10.202 and the wireless being 192.168.1.202. I was able to connect to either, not sure it would be classed as a VLAN.

This would be worth a read https://raspberrytips.com/access-point-setup-raspberry-pi/ 

If I was you, I would be looking at 3rd party routers which are more flexible/configurable than a Plusnet Hub, maybe one with a VPN server for external connections.