Raspberry Pi - Wifi

Reading time ~3 minutes

So… I’m going to start my ramblings by talking a bit about my trek through configuring a damn Raspberry Pi to work the way I wanted to. Specifically, I wanted to be able to SSH into the damn thing whenever I may so desire, regardless of what device I have with me or what networks I create…

Note: throughout this post I’ll be considering a complete lack of peripherals: keyboard, mouse, screen, etc. Anything other than the SD card and a WiFi dongle.

That means making a hotspot out of the Pi itself

Fortunately, I had one of the few adapters known to be able to host a network, so I started playing around… from around 00:00 in the night to about 6am. It wasn’t working right.

In the end, I now have a functional default behavior on the Pi: create a password-protected APN with

to which I can connect, and configure the
for any existing networks.

This way, whenever I’m going somewhere new, I can just get the Pi out, connect to it with WiFi, configure a network, and then go online with both my laptop and Pi at the same time. It’s a very good backup and boot for working with a Pi anywhere without keyboard and mouse and a screen and whatnot.

I’ll update in the morning with a link to the guide I followed.

Some tips I can give to people…

  1. If you’re configuring a static IP to use with

    do NOT allow hot swap for the interface (found at
    ). It will mess things up, especially at boot.

  2. Do NOT attempt to do anything crazy, or confuse ad-hoc networks with APNs, routers, and so forth. The guide that I followed was meant to pipe an ethernet connection into a wifi one, but for the most part, excepting the

    routing, everything was the same. All I needed was the networks. I have found, however, guides (reached via
    raspberry pi create wifi ad-hoc network
    type google queries) that teach you how to create a local, rasp-only ad-hoc network. In simpler terms, a virtual network, a simulation, and nothing more since it cannot reach any other device than the Pi, through any interface whatsoever. Which is fine. It is an ad-hoc network, and it might be useful in some cases. But it isn’t what I wanted.

  3. Create some of your own boot scripts so that you may switch modes whenver you want. For example, I had something like:


# Switch network mode to "other", aka look for existing networks
# instead of broadcasting the secure dev backup
# File: other.sh

# Shut down the APN services
sudo service hostapd stop
sudo service udhcpd stop

# Switch interfaces (so I don't have to do IPs and modes manually)
# – note, backups exist in .other and .own format
sudo cp /etc/networks/interfaces.other /etc/networks/interfaces

# Restart networking to start looking for other networks
sudo /etc/init.d/networking restert

# Or this, why not?
# sudo ifdown --force wlan0
# sudo ifup wlan0

# And now, just to make sure that network 0 is being enabled
# – note, this is pretty much hardcoded. Optimally, one should
# get at least the number of networks in wpa_supplicant,
# iterate through them, and enable them. Also, note that this
# is not mandatory, as eventually wpa will connect you down the
# road, especially if you're using wpa-roam instead of wpa-conf
# in the interfaces file
sudo wpa_cli enable_network 0

to use to stop broadcasting its own network, and start looking for configured ones (be a consumer). Normally, if you try to run this through ssh, you might fail due to the connection being broken before setting the interfaces, for example. A simple fix is to use screen to deal with it, like so:

screen -bm bash other.sh

Well, I’ll update this in the morning with more juicy bits.

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