Noob Question: Netgear DM200 in Half Bridge mode

Hi folks,

I have a Netgear DM200 modem in full bridge mode hooked up to a DIY router which handles the PPPoE credentials etc. To this i've added a set of eero Pro mesh devices, currently double-NATing.

I'd like to scrap the DIY router and just use the eero to manage my home network. However, annoyingly, the eero does not support PPPoE.

I've done some reading and it sounds like what i'm after is Half Bridge mode - whereby the modem will handle the PPPoE connection but otherwise just bridge the WAN IP to the LAN port.

I understand the DM200 is supported by OpenWRT and it sounds like this would be doable, but i'm unsure how to go about this. Any help / pointers would be appreciated. I also have a BT Home Hub 5 (I think the 'A' model) and a Plusnet One Hub which I could use instead of the DM200.

Ideally I want the network downtime to be minimal, so i'd like to plan as much in advance as possible.

Thank you!

While you can get rid of the "DIY router" that way, it won't really provide a means of "half bridge mode" or avoid the double NAT (assuming the eero pro don't offer a plain AP mode). If you handle the PPPoE session on your 'modem', it will automatically (have to-) become a router - so you'd save the physical device of the "DIY router", but not its function.

In terms of performance, DM200, BT Home Hub 5 Type A and Plusnet Hub One are identical - the later two 'just' have wireless and more flash/ RAM - the initial OpenWrt installation would be considerably easier on the DM200 than the bthub5 (BT or Plusnet, I consider both interchangeably from here on). As a router, the performance of lantiq VRX2xx devices in general is rather at its limits around 100 MBit/s (only possible with software flow-offloading enabled, without that you'd be more the in ~85 MBit/s range max.), in pure modem mode it's less of a (potential-) bottleneck (as the router behind it has to do the heavy lifting). If your ISP requires vectoring, you'll need to supply a vectoring enabled modem firmware blob for either of them.

Personally I'd prefer to use the bthub5, because of the bigger flash/ RAM (especially the reserved kernel partition size on the DM200 is rather limited), but I realize that doing the initial installation probably isn't that much fun (opening the device and attaching a 3.3V serial console to very tiny vias).

The OpenWrt/LEDE Installation Guide for BT Home Hub 5A is very useful for either of them, as well as the device pages on the OpenWrt (and the different initial installation options for the bthub5 presented on the ebilan site).

Thanks for the info. Re: HH5/Plusnet - i'm not confident at hooking up serial connection to tiny things (I tried soldering years ago, I just dont have the steady hands!) so i'd lean heavily towards the DM200 as I can use the firmware update mechanism directly.

So, once flashed, its possible to set up such that the device boots, establishes the PPPoE connection and then transparently routes the WAN port to the LAN port, such that a device connected to it gets my WAN IP? If it helps, I have a static IP address...

Thanks for the help!

There are solderless methods described on the ebilan site, personally I've been successful with masking tape and tinfoil on my BT Business Hub 5 Type A - it's doable (and will take around an hour), but certainly less fun.

Yes.

No, whoever/ whatever terminates the PPPoE session owns the WAN IP and will be the NAT router.

Ok, good to know, so double NAT is unavoidable. I hoped there was some way to 'bridge' it without needing the downstream device to initiate the PPPoE session. Thanks!

This would be all trivial and easy, if the eero pro would support PPPoE itself.

I know, right! There are a lot of users requesting the feature. I got a set of 3 eero pros for free, in return for technical feedback (this was before they launched here in the UK) so I don't really want to switch to another system, but the double NAT thing is bugging me...

Btw. I'd probably reserve the dm200 as-is as pure modem, for the -unlikely- case of the eero pro ever gaining PPPoE support - the bthub5 just is a better router (more ethernet ports, more flash, more RAM - the dm200 is really hard on the lower limit for that, especially its fixed kernel partition size with a look into the future and growing kernels), maybe consider buying a pre-flashed device if you're worried to install OpenWrt yourself.

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Technically speaking the ipq4019 based eero pro should be supportatble by OpenWrt as well, that would obviously require someone to do the actual porting work and would lose all the cloud based features.

That may be a good call. Ok thanks!