[PLUG] Question on OpenWRT and wireless bridging

Ted Mittelstaedt tedm at portlandia-it.com
Sun Dec 1 05:44:19 UTC 2024


Hi All,

 

So I have a network that (among other things) has several devices on it that
have ethernet only ports and are not conveniently located to be able to run
cable to them.

 

So for a number of years I have made do with so-called "wifi-to-ethernet"
bridges using DD-WRT.

 

DD-WRT had a nice "client bridge" selection in it's GUI that with one click
would allow you to create a client bridge.

 

Unfortunately, a few years ago Broadcom made some changes in their binary
blob wifi drivers and it damaged the house of cards that client bridging was
built on.

(DD-WRT supports Broadcom devices you see, and these devices used to be far
more common on the used market)

 

The 10/28/2021 release of DD-WRT is the last reliable release that supports
a client bridge on Broadcom gear.  In recent years the client bridge

Functionality has been completely eliminated in favor of "station bridge"
from DD-WRT even on Broadcom gear.

 

DD-WRTs "Station Bridge (routed)" configures the "relayd" daemon and it
works well on devices such as

The TP-Link TL-WR940ND v4/v5 and the Linksys WRT400N which OpenWRT USED to
support but now turns up it's nose at.  OpenWRT also

Supports relayd.  Unfortunately, "Station Bridge" is only reliable if you
have ONE device behind the wifi AP while the old "client bridge"

That was in the Broadcom driver allowed more devices.  Fortunately, these
older AP's are cheap enough to use 1 per device.

 

Anyhoo, I came into position of 2 little Netgear WNR2000v5 wifi routers and
decided it was time to see if I could duplicate this functionality on

OpenWRT.  (DD-WRT does not support these models, unfortunately)

 

I loaded version 18 of OpenWRT onto these devices (there is a
user-contributed build of OpenWRT for this model out there that thoughtfully
includes the

Relayd daemon) and dug up the instructions here to do this:

 

 <https://gist.github.com/AzimsTech/fee582c7c5a89e9295e78f4c8bbda824>
OpenWrt Wireless Network Bridge (With IPv6 Support) . GitHub

 
<https://wiki.terrabase.info/wiki/WRT_Router_Series_Wireless_Client_Bridge_M
ode_with_OpenWRT> WRT Router Series Wireless Client Bridge Mode with OpenWRT
- Wiki.TerraBase.info

 
<https://www.nerd-quickies.net/2019/08/20/setup-lan-wlan-bridge-with-openwrt
-luci/> Setup LAN/WLAN Bridge with OpenWrt (LuCI) (updated) - Nerd Quickies

 

After sorting through the various misconceptions in these instructions I
came up with these instructions - and they work - with one small problem:

 

1) Factory Reset router (either from command interface or from hidden reset
button on bottom)

2) Make sure the 18. lede special build of OpenWRT is loaded on the router

3) Configure PC with 192.168.1.80 and secondary IP of 172.16.100.80

4) Login to router and set password (system, Administraton)

5) Network, Interfaces set Ethernet interface to 172.16.100.8.   Clicking
Apply, Unchecked never works here.

6) Once it takes, remove the secondary IP address

7) Put in Gateway and Custom DNS servers

8) Set Ignore DHCP for ethernet interface

9) Network Wireless, remove master interface

10) Wireless, Scan, Join Bit O Heaven network  (set encryption to AES)

11) Status, make sure it's associated, Diagnostics Ping 75.75.75.75  make
sure it responds

12) System Startup , relayd  enabled

13) Network, Interfaces, Add Interface, name stabridge. Protocol Relay
Bridge, Submit

14) In Relay Between Networks that appears, dropdown  lan and wwan check
both save and apply

15) Network Firewall, Zones Add, name bridgezone change Forward to Accept,
in covered networks select Lan wwan, save & apply

16) Change static IP in PC back to DHCP and it should get an address, should
work

 

The small problem is that even after saving the configuration - once the
router is rebooted - the client bridge does NOT work

On restart.   Relayd is running, the firewall and additional interface is
there, everything seems to be in order - it simply does not

Pass packets.  I can telnet into the router and ping the Internet, it does
re-associate with the wifi network.

 

I can factory reset the router and rebuild the config again - and it works -
passes packets and so on - until reboot.

 

The DD-WRT routers configured as station bridges have no problems with
saving their config and restarting station bridging.

 

I am wondering if POSSIBLY the problem might be in some kind of startup
ordering issue - that is, relayd has to be started after

The AP has associated - or after the soft interfaces are created - or
something.

 

Of course, it would also be cool to build a newer OpenWRT for these devices
- there ARE community built versions of OpenWRT 22

For 4MB flash devices such as the Netgear WNR1000 and the WNR2000v3, - so it
is possible to do it (if you delete the non-essential stuff)  But,

This is a basic networking function and I don't think the versions of things
are too old.

 

Anyone have any suggestions?

 

Ted



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