Wifi bridgung.

[The Natural Philosopher]

Ok, I've looked up loads of stuff on the interwebbery, and all the
solutions to make a pi into a wifi *bridge* are actually making it into
a router, with its own DHCP etc

Not the same as the average wifi access works in a WAP at all.

Can this actually be done at all?

I basically want a pi on the network to be connected to by wifi clients,
and forward the packets over its ethernet to the main LAN. And let the
main DHCP server do the business.



--
"The great thing about Glasgow is that if there's a nuclear attack it'll
look exactly the same afterwards."

Billy Connolly

[mm0fmf]

On 01/02/2024 18:55, The Natural Philosopher wrote:
>
> Ok, I've looked up loads of stuff on the interwebbery, and all the
> solutions to make a pi into a wifi *bridge* are actually making it into
> a router, with its own DHCP etc
>
> Not the same as the average wifi access works in a WAP at all.
>
> Can this actually be done at all?
>
> I basically want a pi on the network to be connected to by wifi clients,
> and forward the packets over its ethernet to the main LAN. And let the
> main DHCP server do the business.
>
>
>

You set it up as an AP and enable ip4 forwarding so so stuff received on
the wifi goes to the ethernet and back. I've got this on an old Pi but
it's not handy or I'd look at the config.

[The Natural Philosopher]

So it is possible?
I found something called bridge-utils that implies it can be done, but
the Pi is now bricked since I did an upgrade on it.

--
Microsoft : the best reason to go to Linux that ever existed.

[Andy Burns]

The Natural Philosopher wrote:

> Ok, I've looked up loads of stuff on the interwebbery, and all the
> solutions to make a pi into a wifi *bridge* are actually making it into
> a router, with its own DHCP etc
>
> Not the same as the average wifi access works in a WAP at all.
>
> Can this actually be done at all?
>
> I basically want a pi on the network to be connected to by wifi clients,
> and forward the packets over its ethernet to the main LAN. And let the
> main DHCP server do the business.

Not done it on a Pi, but used to use bridges with Xen virtual
networking, follow steps 1..5 but substitute wl0 (or whatever) for eth1

<https://tldp.org/HOWTO/BRIDGE-STP-HOWTO/set-up-the-bridge.html#BASIC-SETUP>

[Theo]

That's routing not bridging. With bridging you create a bridge device and
attach two network devices to it - packets received on one device are sent
to another. It's as if the wifi and LAN are one network. Most consumer
routers bridge their wifi and LAN ports.

If you want to go ethernet->wifi->ethernet there are some issues with the Pi
0W/3 hardware not having the right features in the wifi chip:
https://raspberrypi.stackexchange.com/questions/51057/raspberry-pi-3-model-b-wireless-bridge-to-ethernet
Not sure if the same applies to the 4 and 5 or if they fixed it in the
hardware.

(I previously had a better source than that, which I can't find now)

If bridging doesn't work then you can still route, ie put wifi and LAN on
different subnets and have forwarding rules to pass packets between. Which
is probably why most of the guides out there are discussing that not
bridging.

You can also use proxy ARP to make IPv4 routing look like bridging:
https://raspberrypi.stackexchange.com/questions/88954/workaround-for-a-wifi-bridge-on-a-raspberry-pi-with-proxy-arp
and for IPv6 there's Proxy NDP.

I've done Proxy ARP on other machines long ago but not a Pi.

Theo

[mm0fmf]

Mea culpa. You're right that's routed mode. My memory gets hazy about
this as I think I tried bridging but it wouldn't (or I couldn't) make it
work. This was with a PiB+ and Ralink RT2870/RT3070 USB dongle. So I
went with a routed solution. But it was a long time ago. Sorry for
raising false hopes.

[Tim Morley]

In article <upgpfv$26dse$1...@dont-email.me>,

The Natural Philosopher <t...@invalid.invalid> wrote:
>
>Ok, I've looked up loads of stuff on the interwebbery, and all the
>solutions to make a pi into a wifi *bridge* are actually making it into
>a router, with its own DHCP etc

Try this in the standard docs:

https://www.raspberrypi.com/documentation/computers/configuration.html#use-your-raspberry-pi-as-a-network-bridge

Tim