Second WiFi adapter

[StoneCrab]

In reading through the possible network configurations, it seems to be suggested that if you want to use the Pi as a hotspot, you should either install a second WiFi dongle or use USB WiFi tethering from an Android for the Marina connection.

Have these configuration setups been documented? I see the recommendation but no how-to.

I don't know how to setup a USB tether on the Linux side, and as to adding the second adapter, following the usual procedure for editing wpa_supplicant and the interfaces files, results in unusual behavior when the AP is turned on in the OpenPlotter-Network configuration. Buster sees the second dongle. I just haven't had any luck configuring it.

The lines between OpenPlotter, Linux and OpenCPN are a bit blurry since a running OP AP installation has nothing in the network interfaces configuration file, yet it works fine with just the onboard WiFi on a Pi4. The Network configuration screen offers the option to use the onboard WiFi as both the Access Point and the I-net adapter but warns that the configuration is unstable. Based on this warning, I am trying to configure the second USB WiFi adapter. So far, no love.

If this needs to be posted somewhere else, let me know.

[rgleason]

Perhaps as you learn, you can take notes and provide this supplemental information to the Manual?

[Dsanduril]

Can’t help with the second USB WiFi adapter as I haven’t been down that road. We have OpenPlotter on a Pi 4 and USB tethering to an Android phone just works. Plug the phone charging cable into the Pi (actually to a powered hub connected to the Pi) and enable USB tethering on the phone. In OP the tether immediately shows up as network connection USB0 and internet is available.

When we are using WiFi instead we use an external WiFi adapter and connect it to the Ethernet port on the Pi.

The Pi serves as our boat’s WiFi AP so in both cases we bridge the USB/Ethernet to the AP to provide internet access to the whole boat.

I prefer using the external WiFi router connected over Ethernet as it allows me much easier configuration of firewall rules, etc. That can be done in Linux, but I’m much more familiar/comfortable doing it in the router.

[StoneCrab]

Originally Posted by Dsanduril

When we are using WiFi instead we use an external WiFi adapter and connect it to the Ethernet port on the Pi.

The Pi serves as our boat’s WiFi AP so in both cases we bridge the USB/Ethernet to the AP to provide internet access to the whole boat.

The bridge to the whole boat that you mention is what I want to do. Apparently there are many ways to do this. I am interested in your solutions.

I currently make a laptop a "mobile hotspot" but the laptop is unreliable in that it doesn't make the connection persistent. A fading signal drops the WiFi and the hotspot. The WiFi may return but the hotspot doesn't restore itself. So I am continually maintaining the connectivity.... well often enough that I want a better solution.

Windows is supposed to be able to share a WiFi connection over Ethernet, which would allow me to use the Pi with OpenPlotter in headless mode but still have the internet on the Pi. Although the bridge gets formed on the laptop running Windows, the Pi (or anything else connected to Enet) doesn't get routed out to the internet. I've never had success with the Windows bridge.

The Pi does a good job acting like a router / bridge and is like a dog with a bone. I've had very consistent connections, I just can't seem to get the two WiFi dongle's working when AP is selected. It goes sideways with two.

Originally Posted by Dsanduril

I prefer using the external WiFi router connected over Ethernet as it allows me much easier configuration of firewall rules, etc. That can be done in Linux, but I’m much more familiar/comfortable doing it in the router.

Dsanduril, can you tell me more about what you are doing here? Maybe I need a new router, but mine can't log into a WiFi network. Other computers can log onto it, but the traffic gets routed to the router's WAN Enet connection.

How do you receive the challenge screens to finish the login process? By Challenge, I mean, for instance, say you go into McDonalds and they have free WiFi, you pick the SSID and it sends back an IP address for a page where you acknowledge their terms and conditions while looking at sexy food pictures. After the acknowledgement is received you get access to the internet.

I'd be happy to document my final solution.... too soon right now. Even when I get things working, there is always that next step that takes me backwards. My idea for documentation would include pointing out that some of the options and settings are actually menu items in OpenPlotter, others in Raspi-Config or elsewhere. Not all things need the terminal command line editor.

Which brings me to a point of confusion about the two WiFi solution. I just configured OpenPlotter ver 5.2.0 and out of the "box" the onboard WiFi will do AP and bridge Ethernet, but if you look in the wpa_supplicant and interfaces configuration files.... there is nothing in there, yet adding a second WiFi dongle or putting one in monitor mode requires a lot of code in both these files. Seems inconsistent. It must be because configuring two dongles through these files will work until you turn on the AP mode and VNC. Then it blows up.

Thanks

[Dsanduril]

Stonecrab,

we're about to push off from the dock and won't have internet for a while, but I'll do my best to answer, although I don't have all the configs handy. For the most part I now just use USB tethering to my Android phone as that works and is pretty much the only service available up here.

When we did use WiFi I had several different devices. The current collection is a Ubiquiti Bullet installed at the masthead by the PO (used a lot in anchorages and marinas for long-distance WiFi) and a LogiLink WiFi puck (smaller than a deck of cards) used for portable stuff. Also have used a MicroTik and an old Linksys router (12V power so it worked on the boat) that I flashed with DD-WRT and OpenWRT.

Pretty much all of them were configured the same - as a bridge device between the WiFi client and the Ethernet port. Configured this way the pretty much 'disappear' on the network. For challenge screens usually the first machine to try to access the internet on the Ethernet side would get the screen and could answer the prompts. This does depend on the challenge system used by the other network. We've had three types; one machine responds and then all is good, each machine has to respond once (and this may or may not be suitable if they are pay systems), and systems where I have to do a dance because the challenge ties to the MAC of the responding system rather than the WiFi device. This last one can be no big deal (after response on the Pi all other traffic goes through the Pi and so looks like it came from there) or one where I get into MAC spoofing which can be a pain. All depends on what the other guys have set up, at least as far as we have found there isn't a universal solution.

One caveat to this configuration (which is mentioned in passing the OP documentation - where it says not to connect the OP in router mode to another router) is that you have to make sure there is only one DHCP server on the network. I usually leave that to the Pi/OP and remove it from the WiFi device because that's just easier for me.

Sorry I don't have detailed configs at the moment, while we're out I'll fire up the Bullet and grab the configs and if you're still working on it at the weekend I can come back and post a few details.

Sorry that wasn't more help, was hoping a I might just post another option, but instead I think I may have opened a distracting can of worms.

[barnakiel]

Not sure which Linux you are using but Ubuntu sucks big way on the AP / wifi font. Nothing works there. Most drivers are not documented, etc.



Whether you need and extra card or not depends on what card you already have. Some can work on both frequencies (2/5) and then you can have a AP on one fqcy and client on the other.


But I would not waste my time fumblin with Linux. Android does work wol both as Ap and Client or both BUT tethering from Android is ...


Maybe if you mak a quick hand drawn schema of the components in place and explain what you want to achieve someone here will be able to tell you how they did it.


b.

[StoneCrab]

Thanks guys. I will be slogging away at this until it works. I have a few more links to read.
The OS software that I'm running is called Buster. It came on the OpenPlotter image.