Using OpenWrt as dumb ap on x86 help for config

Hello all,

my idea is : wifi signal is low in my office/basement (which has net from rj45 switch/router from 2 stories up)
I can use my old core2duo booting from a standalone usb key, with a usb wifi adapter as dumb ap with openwrt, nice and easy..... well not that much...

1st problem, the wifi adapter is a Dlink Archer T4U Plus with a... realtek 8812Bu chipset (covid urgent buy).
After weeks of fight it seems to be "working"...but may be it's my pb...
2nd pb don't ask me how, my files were lost to a coned shortage due to an "infrastructure problem"... and I have been incapable of making
this realtek driver working again with a fresh homemade openwrt 22.03.3 install,
so the image I have, is the only one that make this usb thing...blinking
(I'll wait to upgrade/modify my image when Linus T or some bearded geek god will have the rtl88xbu driver ported to the kernel :D)
If somebody wants the image I can give it no pb...

I am not absolutely sure the driver is working a 100% correctly but it seems.

things I can do :
in luci
I can scan with "radio1" its working and detecting wifi around me
I can join my wifi JAC to be sure it was working and it did

things I cannot do
in luci
have the wlan0 interface showing up
use the radio0 "scanning"
have my ssid "appearing" from this conf
changing this usb...adapter

things I want to do
make this working the best as it can
I don't need 1GBPS over wifi
I just want this to broadcast my main ssid and be able to connect to my network (without losing signal/wifi if possible)
with phones/tablets/laptop whenever I am in my office

Any help would be greatly appreciated :slight_smile:
Joinng some printcreen.


Just about any cheap plastic wireless router starting around 20 bucks will do a better job, at zero effort. Also keep in mind that your core2duo probably chugs around 115-130 watts out of the wall, continuously, compared to 5-20 watts for a plastic router, even in areas with cheap electricity, a dedicated AP will quickly pay for itself.

USB wireless and AP usage is already bad enough to begin with, but Realtek USB wireless is… [CENSORED]


it's a cheap DIY project to check if it's doable and wired AP can be a lot better than verizon g1100 :slight_smile: the huge effort is all the cost I can afford before the "industrial" trial (and the wife acceptance) :smiley:
With an old pci graphic card, no hard drive and good under-clocked I see less than 40W on the plug so not that bad and it will plugged only from time to time.... and a lot less of electronic waste.
My original idea was to use rapspi, but due to the shortage and the price it became not worth it, and for the not so far future, the use of openwrt to do mesh on some old laptop/pc with usb stick openwrt image and usb dongle or pcie wifi card, can be fun.
So this sh.ty realtek may be used more than it deserve to :smiley:

But for now I need to understand why my config is not working and what I can do to fix it....if I can

PS: no I will not throw this wonderfully rotted tp-link to the garbage.... it will burn due to worn-out, or wrong trial and lot of error, first :smiley:
if it's too easy it's not fun :wink:

Does "cheap DIY" apply to the proof of concept test, or the actual deployment of a proper AP?

AFAIK, the G1100 isn't terrible (for wifi performance, that is.... the rest of the firmware is indeed terrible), but it certainly isn't great. But it's actually a tall order for a USB wifi adapter (or even a PCI one) to outperform an actual AiO wifi router, so you're not likely to find it a compelling demo.

cheap DIY because as an IT guy I/we all have parts and/or old computer/eeepc/laptop lying/dying around in the family/friend circle too, if instead of become e-waste it can be reused it's better than nothing.(that's why I am using the dlink I bought during covid for windows machine) the old 8400 works wonderfully on win10 for my kid, that's why I am using a usb key in standalone.

I agree that the g1100 is not that terrible but it's out of the update cycle now that the 3100 has taken it's place, and well it still is my wifi5 (and lan) router :).

It's just that with some "love" it can be less problematic than having a commercial wifiAP/mesh/router rarely updated, and not upgradable for people who don't need a 2.5GBP/S wifi... reusing not so old tech, not just routers...

And helping me having the wifi access in my office (which is my first concern right now :D) (so POC and usefull :))

I can appreciate your approach here... a few counter-points:

  • As stated earlier by @slh, the power consumption is high -- 40W is still more than 10x the power consumption of my UAP-AC-PRO (3.7W as I look at it now).
  • A USB or PCI wifi adapter may perform well in sta mode, but most of them don't do nearly as well in AP mode because they may not be well suited for handling multiple concurrent streams (many are 1x1 radio systems, compared to most modern APs that are at least 2x2 MIMO, with many easily supporting 4x4 MU MIMO or wifi 6 if you're in a higher density situation with lots of client devices).
  • It is true that many consumer grade AP vendors don't continue support/update the firmware on their devices... but...enterprise gear is different. Ubiquiti, for example, is still providing new firmware for the UAP-AC-PROs which are ~11 years old now (the quality of the newer firmware can be debated, but they are still fully supporting the product).
  • And... there are many APs that can run OpenWrt, so you can avoid the issue of outdated/EOL firmware situatiosn from those vendors.

I totally get that you've got stuff on-hand and you don't want it going to a landfill/e-waste until it really needs to, but the environmental impact, cost of ownership (as a function of engergy consumption), and performance are all worse than a proper AP.

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…to add upon this, I've bought quite amazing devices (routers/ APs) for 5-15 bucks (EUR/ USD) on the second hand market, but even less amazing -but decent- stuff can be found regularly.

At least around here, the 802.11ax based D-Link DAP-X1860 (mt7621a+mt7915DBDC) is occassionally on sale for down to 15 EUR, new, from regular physical&online stores - it just needs a little patience and persistence.

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  • I agree that the TCO will be higher than an AP no discussion there, even if my 8400 with 6GB of ram, does not cost me anything anymore it's from 2006 :slight_smile: , but in term of power consumption, compared to a lot of houses in the us, western Europe, japan or south Korea, just residual use of energy 40w... well even 100W is unfortunately nothing...

  • The fact that usb or wifi adapter are not really suited to be AP, well, that's why I am doing this too, my experience can validate this, or not, at no cost but time and electricity... wait Dlink/realtek are telling me that my wonderful Dlink AC1300 with it's 2 antennas "MU-MIMO for higher Efficiency".... has to be good. right? :smiley: :smiley: and it will be just for 2 may be 3 users at the same time, not a full 50 people's floor...

  • I did not know that ubquiti was doing this, good point for them, you and a lot of people using them with openwrt, but a new basic usb wifi6E stick is less than 40$/€ on amazon, and wifi 7 will come out soon... How will your wifi5 ubiquiti router do ? will you have a way to 'upgrade' the lan to 2.5-10GBPS or wifi ? will it have enough cpu power to be used with PSK3X or the last ZZMB encryption ? how your 2013 hardware will be in 5 years ? Embedded device are efficient, but not always very long lasting....

  • So is this the best solution, no...a "work around", maybe, we'll see

But right now it's not working, so if you can help me to make it work I'll be happy to tell you that you were right (or may be wrong who knows) and that realtek did a wonderful job with this chipset :rofl:

experience is everything :slight_smile:

On a relative scale, that is true. Your personal setup, on an absolute scale, is not going to make a dent. However, as we look at the aggregate, the picture changes. One person deciding they're not going to drvie a single-occupancy vehicle (and instead using a carpool, public transit, or self-powered commuting like cycling) will make almost no difference with resepect to traffic or environmental impact... but the more people who make those same choices, the better things become.

The U6-lite is ~$99 USD. Yes, more expensive than that 6E stick, but still pretty affordable. And likely far better performance thant he 6E stick you're talking about, but it doesn't require a whole other system to interface with the network since it is an ethernet device (rather than USB). And yes, Wifi 7 will come out... how will my wifi5 device do? Very well, actually. Wifi 6/6E/7 make improvements that are relevant mainly to higher density operation... Wifi 5 is still great, though. And, FWIW, I run at 20MHz and 40MHz (2.4 and 5G, respectively) channel widths becaue I favor consistency/stability, reliability, and 'not crowding the airwaves' over raw speed. My connections are rock solid. And I have a mix of Wifi 5 and a few Wifi 6 devices in the house, but no need to upgrade the APs.

Trust me, I do believe in using devices as long as possible -- I've got a 2009 (!) Mac Pro that is my daily driver (it has long since fallen off the software update bandwagon due to its age), and my OpenWrt based VPN endpoint is a RouterStation Pro from maybe more than a decade ago. But I am also a firm believer of the right tool for the job... an x86 box makes for a great (although often power-inefficient) router, but it is not the best option for an AP. Likewise, there are lots of APs out there that are great as APs but can't route at any reasonable speeds.

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I completely agree with you, and as I have no car, just cycling, I'll allow myself to waste on some days 400W if that's ok with you :wink:
For the wifi evolution, like you few wifi 6 devices for now, but with each new year and company's/school brand new gizmo (sound system, tablet and even fridge lol) are using wifi 6E... no need to upgrade the wifi 5 AP.... well depends... how many devices will it be able to support ? and rock solid is good for working, but for teenagers and old gamers like me, speed and latency matters too (that's why I am still with an old cat5E rj45), but close AP with wifi 6E compete with rj45 nowadays...and wifi 5 has no way to handle a lan NAS backup, gaming and streaming on 2 tv, 5 or 6 phones at the same time... except if you have various AP or a good mesh... it's getting there but not quite yet...
And I am not speaking about the not so far neighbors...with their microwave messing the 2.4ghz band :rofl:
That's why WiFi is evolving, and needs to.

My first homemade router was an all steel/aluminium gateway 2000 p2 233 with a mandrake distro(RIP) and an usb modem working as router(yes a lot of iptable :D)/print server, the motherboard died a few years back after almost 20 years of 24/7 uptime, power hungry with a 200W power supply from 1995 may be :slight_smile: but its total ecological footprint is so low compared to a number of today's plastic router that will last a few even 10 years, and on witch you cannot change any hardware in case of failure...

Even if it's a very interesting discussion, it does not help me to make this thing work...if it can... any idea for my original issue or as it's not eco-friendly I do not deserve any help ? :slight_smile:

Just about anything even with stock firmware can be repurposed into a dumb AP, for example the cheap DSL modem/gateways that companies provided to customers. All that is really needed is an option to turn off the DHCP server.

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Actually, you made me think of something... how can I be sure the driver of the realtek I am using is AP capable...
is there any command line/info in Luci I can run to know that ? may be that's my problem....

Holy s..t ! I knew that Linux had daemons, but not witches!
Just kidding. It's an obvious typo error, but it's funny to read.

iw phy0 info | grep "Supported interface" -A 10

You may have to change phy0 with phy1 or wlan0, etc.

not a typo :sweat_smile:, trying to make openwrt working with the rtl8812bu is sorcery :rofl:

root@OpenWrt:~# iw phy0 info | grep "Supported interface" -A 10
        Supported interface modes:
                 * IBSS
                 * managed
                 * AP
                 * monitor
                 * P2P-client
                 * P2P-GO
        Band 1:
                Capabilities: 0x1963
                        RX LDPC

Hum, so according to this, it might possible...
But each time I try in Luci to go to Network -> wireless -> Edit the SSID Openwrt to make some change in it, like just changing the country code for example and enabling it and

the save&apply... nothing
and yes I lost one of the 2 radios (2.4ghz or 5ghz I don't know)...after a reboot without doing anything.....the realtek's curse
edit : or not :crazy_face:

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Apparently yes.
EDIT : I'm sorry I got confused. "acces point" mode means that the router can broadcast wifi to clients. This is the default mode of a router, so it is obvious that iw replies this as a possibility. If you want to configure your router as a dump AP, you need some configuration.

This realtek wifi card can only provide one wifi network at the time, as most wifi cards.

It's always been one radio. It can be set to either band but can't operate on both bands at once.

Check the first images I joined to the post : radio0 and was after my first access to Luci
but if it works I will be a few meters away from the AP either 2.4 or 5 will do....
For me "acces point" just mean some piece of hardware that creates a bridge between "cable" local network and wifi local network, just a switch with wifi capabilities.

I followed the tutorial you gave and others... and I am not catching any AP with my phone/tablet coming from this...
if you notice something wrong....
I just checked to be sure that the channels used by my g1100 were not the same than on Luci.
As I could not change the encryption in Luci I put it in the config file.

config wifi-device 'radio0'
        option type 'mac80211'
        option path 'pci0000:00/0000:00:1d.7/usb2/2-5/2-5:1.0'
        option channel '36'
        option band '5g'
        option country 'US'
        option cell_density '0'

config wifi-iface 'default_radio0'
        option device 'radio0'
        option network 'lan'
        option mode 'ap'
        option ssid 'JAC'
        option hidden '0'
        option encryption 'psk2'
        option key  'ofcourseitsnothispwd'
config interface 'loopback'
        option device 'lo'
        option proto 'static'
        option ipaddr ''
        option netmask ''

config globals 'globals'
        option ula_prefix 'fde9:3fb1:6b09::/48'

config device
        option name 'br-lan'
        option type 'bridge'
        list ports 'eth0'

config interface 'lan'
        option device 'br-lan'
        option proto 'static'
        option ipaddr ''
        option netmask ''
        option gateway ''
        list dns ''

I tried to put another ssid name just to see if he became visible....but no...

Sry if I am a pain, but I had hope to make this work :smiley:

Read the log file for wifi related errors. The iw list can be wrong, what I see on the web is the Linux drivers for this chip do not support AP.

You may have seen two radios before because whenever a USB wifi is plugged into a different physical port path, it is detected as a new radio and added to the config file. So if you ever unplug the USB, make sure to plug it back in to exactly the same port on the PC or your configuration will no longer work.

I had no idea for the usb port so good to know thx

For the driver yes I know... if only I did not lose my files I would know the driver that is working right now...most of my trials were made with Nick's driver, but it's hard to know the working one right now as I am not able to redo it... I remember trying (which uses nick drivers too) and sooooo much more...:sweat_smile:
Working makefiles to add kernel_module driver that work are not easy to understand/make...
That's the reason I wanted to know if there was a way to be sure if AP was supported :frowning:

Any specific log file in mind I should check?

OpenWrt keeps the system log in RAM not in a file, use the command logread to view it.
The LuCI options Kernel Log and System Log run dmesg and logread respectively.

Test unknown USB hardware for support on a major desktop Linux. If it can't be made to work there it's not going to work with OpenWrt.