Connecting external mesh system effecting router dhcp [SOLVED]

As per the title, I'm struggling to get my new openwrt network running, but struggling for a week now and getting nowhere, I know its something simple but just my knowledge is limited.

I can see the problem now I think, but how to fix it....

I have a set of BTwholehome mesh discs plugged into the router, and it must be screwing the DHCP server up as devices connected directly to the router show on the mesh network with a totally different ip address??

So my BT mesh system plays havoc with my openwrt router, it seems to effect the Lan DHCP configuration.

My phone has a static ip of 192.168.1.14 assigned to it's MAC address via the DHCP tab in openwrt, works great... But when the system crashes out my phone has it's ip listed as 192.168.1.186 and the gateway is listed as 192.168.1.5 instead of the routers 192.168.1.1

192.168.1.5 is the master disc from the BT mesh setup.

If the openwrt router is the main router, you need to set your other equipment (bt mesh) to work in ap mode only - meaning that they are only braiding wired and wireless and are not performing routing. Or, at the minimum, you must turn off the dhcp server in the bt mesh since multiple dhcp server me on a network will conflict.

They don't have any menu configuration like, just plug and play into any router they say... I've reverted back to stock Netgear firmware for now as it works, and I'm gonna and see if I can take note of all the settings and try see what changes between the two as both file systems seem very similar.

I’d be a bit surprised if there is no way to configure the mesh system at all (sometimes it is a web interface, other times an app, but there is almost always at least some basic user config functionality). But regardless, you can only have a single dhcp server on your network, so you may still find issues even if you’re setup with stock firmware for everything.

I've used the mesh set up on stock firmware for 2 years now without hassle, last night I used it to boost the wifi on a really old Belkin F5D7250-4 router which I used as my R7800 tied itself up in knots with this issue and tftp flashing that late at night wasn't happening.

There is an app and a web GUI but there's no settings for things like making it an AP as that's all it is, it still uses the router for DHCP stuff. (Google BT whole home wifi to see what they are)

It's like openwrt doesn't see it as an Ethernet add on, but integrates it deeper into the file system. I'm assuming it makes a vlan bridged into the set up. Might up end paying a shop to get it set up as I'm struggling.

I don’t know what you mean by this. By default, openwrt is setup as a main router. Everything connects via Ethernet or WiFi. The hardwired disc will appear as an Ethernet device. No devices are integrated “deeper into the file system” and openwrt doesn’t automatically “make a vlan bridged onto the setup”.

Basically you have two systems that are trying to be the main router - both have dhcp enabled and assume they are the gateway to the internet. You must configure one or the other to disable dhcp and ensure that the real gateway is advertised via the active dhcp server.

A better way to approach this is the following:
What is your end goal?
What are you trying to do with openwrt?
What is your desired network topology?

You might be better off simply removing the openwrt router from your network and simply using the bt system, unless there are specific things you need/want from openwrt.

The only things I want the mesh discs to do deal with the wireless signals, my old Stone House has solid redstone walls and the R7800 wifi doesn't reach, these discs fixed the problem entirely, 6 of them throughout the house give me wifi everywhere I need it.

I wanted openwrt over stock Netgear on the R7800 for sqm, ad blocking and to get rid of the buggy stock firmware.

This is what stock firmware shows with the discs connected and working...`

root@NetgearR7800:/$ ifconfig
ath1      Link encap:Ethernet  HWaddr 8C:3B:AD:B6:C5:2D
          inet6 addr: fe80::8e3b:adff:feb6:c52d/64 Scope:Link
          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
          RX packets:2679 errors:0 dropped:0 overruns:0 frame:0
          TX packets:3727 errors:19 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:0
          RX bytes:500986 (489.2 KiB)  TX bytes:1860742 (1.7 MiB)

br0       Link encap:Ethernet  HWaddr 8C:3B:AD:B6:C5:2D
          inet addr:192.168.1.1  Bcast:192.168.1.255  Mask:255.255.255.0
          inet6 addr: fe80::8e3b:adff:feb6:c52d/64 Scope:Link
          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
          RX packets:3422048 errors:0 dropped:66807 overruns:0 frame:0
          TX packets:3588546 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:0
          RX bytes:1456821229 (1.3 GiB)  TX bytes:2859944085 (2.6 GiB)

brwan     Link encap:Ethernet  HWaddr 8C:3B:AD:B6:C5:2E
          inet6 addr: fe80::8e3b:adff:feb6:c52e/64 Scope:Link
          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
          RX packets:3584878 errors:0 dropped:0 overruns:0 frame:0
          TX packets:3308044 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:0
          RX bytes:2811087769 (2.6 GiB)  TX bytes:1513109500 (1.4 GiB)

ethlan    Link encap:Ethernet  HWaddr 8C:3B:AD:B6:C5:2D
          inet6 addr: fe80::8e3b:adff:feb6:c52d/64 Scope:Link
          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
          RX packets:3420627 errors:0 dropped:0 overruns:0 frame:0
          TX packets:3594242 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1000
          RX bytes:1504621503 (1.4 GiB)  TX bytes:2867210290 (2.6 GiB)
          Interrupt:2

ethwan    Link encap:Ethernet  HWaddr 8C:3B:AD:B6:C5:2E
          inet6 addr: fe80::8e3b:adff:feb6:c52e/64 Scope:Link
          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
          RX packets:3584911 errors:0 dropped:0 overruns:0 frame:0
          TX packets:3308081 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1000
          RX bytes:2889509550 (2.6 GiB)  TX bytes:1513879081 (1.4 GiB)
          Interrupt:255

lo        Link encap:Local Loopback
          inet addr:127.0.0.1  Mask:255.0.0.0
          inet6 addr: ::1/128 Scope:Host
          UP LOOPBACK RUNNING  MTU:16436  Metric:1
          RX packets:219523 errors:0 dropped:0 overruns:0 frame:0
          TX packets:219523 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:0
          RX bytes:10054889 (9.5 MiB)  TX bytes:10054889 (9.5 MiB)

ppp0      Link encap:Point-to-Point Protocol
          inet addr:212.69.58.88  P-t-P:212.69.63.36  Mask:255.255.255.255
          UP POINTOPOINT RUNNING NOARP MULTICAST  MTU:1492  Metric:1
          RX packets:3582433 errors:0 dropped:0 overruns:0 frame:0
          TX packets:3305593 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:3
          RX bytes:2810543312 (2.6 GiB)  TX bytes:1512650774 (1.4 GiB)

wifi1     Link encap:Ethernet  HWaddr 8C:3B:AD:B6:C5:2D
          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
          RX packets:0 errors:0 dropped:0 overruns:0 frame:0
          TX packets:0 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:539
          RX bytes:0 (0.0 B)  TX bytes:0 (0.0 B)
          Interrupt:90 Memory:e1c00000-e1e00000

root@NetgearR7800:/$`

I would contact support for the bt WiFi system and find out how to disable the dhcp server.

Or another way to do this is to change the Lan ip address of the openwrt system to a different network - for example 10.0.5.1/24 (could be any rfc1918 address range other than 192.168.1.0/24 or whatever your bt network uses). Then connect the wan of the bt WiFi to the lan of your openwrt router. This will create a double nat, which is not ideal but should work for most things without issue. From there, you can setup Adblock and anything else you want on your openwrt router and it should work.

Keep in mind that this is creating 2 network, so if you connect anything else directly to the openwrt router (wired or WiFi) it will technically be on another network relative to those devices connected to the bt discs.

I would not normally suggest this route - the better method is to make the bt discs work as dumb aps (bridge mode, ap only), but since it sounds like you cannot make meaningful changes to the bt discs, double nat may be the easiest option.

There reply was long winded, but the important bit was this...

the BT solution doesn’t have any routing capability, or complementary services such as DHCP or firewall on its own, but simply sits on the LAN segment created by your router and adds WIFI radios to you existing network.

From what I've read Netgear stock firmware is an old openwrt firmware with Netgear overlay on the top, as this works fine with the discs, what command can I run to see what it's doing/how it's doing it??

This contradicts your earlier assessment of the situation in that some devices had a gateway assignment of 192.168.1.5 which can only happen as a function of a dhcp server on the main disc

I know it does... This is where I'm lost entirely.

On stock firmware, I connect to the mesh discs wifi but the router acts like I'm connected directly to it and gives my phone it's ip address of 192.168.1.14

On openwrt it stopped working, but when I looked at my phones settings, despite the router having the 192.168.1.14 set up with my phones Mac address as a static lease, my phones ip address was 192.168.1.186 or something silly like that... And the gateway was listed as 192.168.1.5 which isn't the router but it is the ip of the mesh disc connected into the router via Ethernet. So I assumed it was 2 DHCP services competing, but there is no DHCP settings on the mesh discs, the company says there's no DHCP built into them and they work plug and play on stock firmware or a cheap Belkin router I have without hassle, if they did had DHCP built in, surely it would effect them too??

Well, let’s look at your config file on your openwrt router.

Post the contents of /etc/config/network and /etc/config/dhcp

I'm back on stock at the minute... But I might have screenshot them last night...

Try these two...

I've took out my Pppoe details, thought it best... Lol