Regarding the detailed instructions for Access point as WiFi repeater, optional with bridge here:

Access point as WiFi repeater, optional with bridge

Since the raspberry pi 3 b+ has only one radio, I'm a bit confused on how this setup provides both an access point to another access point via wireless, whilst still providing a client wireless access.

  • ap0 is a virtual interface created by iw dev wlan0 interface add ap0 type __ap
    – jake
    Feb 15 '19 at 18:37
  • The "answer" you have given below is not an answer. You should put it into this question and delete the "answer".Please read the first line in your screenshot: "Put the SD Card into your RasPi and boot.". Why should it be necessary to boot again? You are already doing the "Next Step: Full upgrade and reboot". Just read the line before you reboot. It doesn't help continuing with the next step before finishing the previous one. Please ensure that Checkpoint3 works direct after first boot.
    – Ingo
    Feb 24 '19 at 11:41

You write:

I'm a bit confused on how this setup provides both an access point to another access point via wireless, whilst still providing a client wireless access.

It isn't right this way. An access point does not connect to another access point. It is only the client wireless connection that connect to another remote access point. The access point of the RasPi does not connect to anything. It only provides the possibility that other clients can connect to the RasPi. So you have two distinct functions:

  • access point - provide connections to the RasPi
  • client connection of only the RasPi to another remote access point/internet router

You can make only an access point or only a client connection. They are independent.

This is possible if the wifi chip supports it. If you look at the link you have used, at the section Details - General you will find:

One problem is that we want to use the same device for a wifi client and for an access point. This must be supported by the wifi hardware. We can check this with

rpi ~$ sudo iw list | grep -A4 "valid interface combinations:"
        valid interface combinations:
             * #{ managed } <= 1, #{ P2P-device } <= 1, #{ P2P-client, P2P-GO } <= 1,
               total <= 3, #channels <= 2
             * #{ managed } <= 1, #{ AP } <= 1, #{ P2P-client } <= 1, #{ P2P-device } <= 1,
               total <= 4, #channels <= 1

The important part is #{ managed } <= 1, #{ AP } <= 1, but you can also see that this is only possible on one channel.

That it can only use one channel for both functions is respected to the fact that the RasPi has only one radio. The channel the access point uses is always the same than the channel the RasPi is connected to the internet router no matter what channel in the setup is defined for the access point.

And there are further restrictions you can read there.

  • So I guess I misinterpreted the first diagram which leads me to believe that ip address (ap0) allows a mobile-phone to connect and that signal is repeated out through wlan0 with ip address The foregoing assumes the RPi can handle both signals, correct? I need a wireless repeater then which this doesn't seem to be. Followed instructions but could never gain access to the internet from ap-connected device. I could ssh into the RPi and ping the internet via wlan0, but whenever mobile device attempted to connect to RPi it would connect but without internet access.
    – jeffschips
    Feb 16 '19 at 19:37
  • @jeffschips The RasPi can handle both signals and it can connect mobile devices on the access point to the internet. So it is working as a wireless repeater. Please follow the instructions at Test access point as WiFi repeater and tell me, which Checkpoint fails for you.
    – Ingo
    Feb 17 '19 at 0:52
  • I get as far as Checkpoint 4 and then cannot access the Rpi via wifi. I can remove the sd card and see it's files on my linux machine if that is helpful. Perhaps I can verify/change files on the SD card? Raspberry Pi 3 b+.
    – jeffschips
    Feb 18 '19 at 14:23
  • @jeffschips No, not removing the SD Card. Let's stay on the RasPi.**Checkpoint4** has 4 commands to check. Does all commands show similar results then shown? What ip address has wlan0 (third command)?
    – Ingo
    Feb 18 '19 at 15:23
  • I mean after failure to connect, I can remove the SD card if you need me to access files therein. Away from device now and will do as you say and post results here later today. Thanks for your help.
    – jeffschips
    Feb 19 '19 at 16:53

The phrase written by you "Next step full upgrade and reboot" - that very phrase is placed between the end of checkpoint 3 and the commands to upgrade and reboot. Why would you include those commands if you didn't want the user to proceed from checkpoint 3 in sequence to those commands? Maybe I'm missing something here but I generally follow the commands in the order that they are entered. If you don't want users to actually update and reboot, why would you have those commands there? But okay, I get it, you don't actually want users to execute those commands. I apologize for the back and forth. Probably just a misunderstanding between languages. And yes, checkpoint 3 works fine after initial reboot. So exactly what then is the next step after completing checkpoint 3 (without rebooting, of course).

  • Again, please don't use answers as comments! Instead use comments. And I think it's time that you please take the short Tour and visit the Help Center to get an idea how things work here. OK, you wrote: "And yes, checkpoint 3 works fine after initial reboot.". So your wlan0 interface has an ip address and you can ping google.com, means you have a working internet connection. The next step is the "Next step: Full upgrade and reboot:" with update, full-upgrade, reboot and so on as described.
    – Ingo
    Mar 9 '19 at 10:21
  • As far as I can tell I can't add code snippets or images to comments, that's why I was using answers. My bad. I have already specified several times that I was able to get an IP address in Checkpoint 3 and access the internet, and that I cannot proceed to checkpoint 4 because the instructions are to do an upgrade and reboot between Checkpoint 3 and Checkpoint 4, which I do do and then after upgrade and reboot, I am locked out and cannot access the raspberry pi. It would seem therefore, that we are going in circles.
    – jeffschips
    Mar 11 '19 at 19:59
  • To answer your comment You can always use your question to clarify your situation with code snippets or images. I have already suggested to do it. You still don't have read the short Tour and visited the Help Center to get an idea how things work here. Note that we are not a discussion style forum and open ended invitations to brainstorm are not appropriate to the format.
    – Ingo
    Mar 11 '19 at 21:10
  • You never told that you are locked out after upgrade and reboot before Checkpoint4. But this cannot be an issue because you have to use a monitor and keyboard/mouse attached to the raspi. I also wrote in bold letters that this is condition. Sorry, but if you don't follow my suggestions and don't read or understand what's written down, I cannot help you.
    – Ingo
    Mar 11 '19 at 21:11
  • Well I thank you for your support. If you see entry dated – jeffschips Feb 18 at 14:23 and your response to that on – Ingo Feb 18 at 15:23 you will see that I did, indeed, say I couldn't access the Rpi. Anyway, I will move on from this. I've learned a lot. And thank you.
    – jeffschips
    Mar 13 '19 at 14:49

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