# Wifi on Ubuntu 18 _server_

## TLDR

1. Install `wpasupplicant`
1. Turn on wifi radios: `sudo nmcli radio wifi on`
1. Check your devices are recognised even if they're not "managed": `sudo iwconfig`
1. Check your wifi (here called "wlp3s0") is capable of detecting nearby routers: `sudo iwlist wlp3s0 scan`
1. Configure `netplan` by dropping a file called `01-netcfg.yml` into `/etc/netplan/` or edit existing file there. See example below.
1. `netplan try`, `netplan generate`, `netplan apply`.

# The backstory

I want to run Ubuntu *server* 18 on my laptop. This by default does not use X windows, so there is no desktop environment. It also by default does not enable wifi. Servers don't usually need wifi and desktop environments, right?

Anyway, I want _both_ wifi and a desktop environment. I actually tried Ubuntu desktop with Gnome on this T420, but Firefox crashed several times, locking up the whole machine. Since I want the laptop to emulate a server environment for development I thought screw it, let's install Ubuntu server on here and just add a light desktop environment.

## TODO

Outstanding items:

* Add other wifi networks
* Switch between networks
* Get `nmtui` to display and switch between wifi networks

## Install Ubuntu

I'm using a Lenovo ThinkPad T420.  On a Windows machine, I followed the instructions on the Ubuntu website for creating a bootable USB stick.

On the T420 I had to go into the bios and move USB up the list so it would boot from the stick.

Installation of Ubuntu was smooth, all went perfectly well.

## Install desktop environment

There are plenty of choices, mine was:

```
sudo apt install xubuntu-desktop
```

## Wifi Networks device not managed

Imagine my delight when I first log into an X window session and realise that the laptop is not connected to the wifi/internet.

## Get wifi working

This is based on a pretty poor understanding of what's going on. Here's what I guesstimate to be the situation.

As of Ubuntu 17, networking is managed by either of two approaches: `NetworkManager` or `networkd`.

Added to this, `netplan` is also used. See [netplan.io](netplan.io)

`netplan` reads YAML config files and generates config files for `NetworkManager` or `networkd`, depending on your preferences.

Also required, apparently, is `wpasupplicant`.

Turn on wifi radios:

```
$ sudo nmcli radio wifi on
$ sudo nmcli radio wifi
enabled
```

Check your devices are all recognised, even if they're not currently being "managed":

```
$ sudo iwconfig
lo        no wireless extensions.

enp0s25   no wireless extensions.

wlp3s0    IEEE 802.11  ESSID:"my-router-name"
          Mode:Managed  Frequency:2.412 GHz  Access Point: 71:5F:58:2F:79:97
          Bit Rate=58.5 Mb/s   Tx-Power=15 dBm
          Retry short limit:7   RTS thr:off   Fragment thr:off
          Power Management:off
          Link Quality=50/70  Signal level=-60 dBm
          Rx invalid nwid:0  Rx invalid crypt:0  Rx invalid frag:0
          Tx excessive retries:12  Invalid misc:59   Missed beacon:0
```

`wlp3s0` is the wifi device in my laptop. If yours doesn't appear.... good luck with that. Maybe try `ifconfig up wlp3s0`

Check your wifi is capable of detecting nearby routers:

```
$ sudo iwlist wlp3s0 scan
wlp3s0    Scan completed :
          Cell 01 - Address: 70:4F:57:3F:78:87
                    Channel:1
                    Frequency:2.412 GHz (Channel 1)
                    Quality=50/70  Signal level=-60 dBm
                    Encryption key:on
                    ESSID:"my-router-name"
                    ...
<lots more - output trimmed for brevity>
```

Again, if your output is different here, good luck!

Configure netplan:

My `/etc/netplan/01-netcfg.yml` looks like this, note that it renders config files for `networkd`:

```yaml
# This file describes the network interfaces available on your system
# For more information, see netplan(5).
network:
  version: 2
  renderer: networkd
  wifis:
    wlp3s0:
      dhcp4: yes
      access-points:
        "my-router-name":
          password: "<wifi password here in plain text>"
        "some-other-router":
          password: "plain-text-password"
        "Public Hotspot With No Password": {}
```

Do not be distracted by `/etc/network/interfaces`! Mine looks like this, note what the comments say, and note that there is nothing else in apart from the comments, i.e. it does nothing:

```
# ifupdown has been replaced by netplan(5) on this system.  See
# /etc/netplan for current configuration.
# To re-enable ifupdown on this system, you can run:
#    sudo apt install ifupdown
```

`ifupdown` is not on my system.

Running this seemed to get things working:

```
sudo su -
netplan apply
service network-manager restart
```

This is confusing. The `netplan` config file renders for `networkd` yet restarting the `network-manager` seems to apply the netplan changes to NetworkManager.

At some point I think I also restarted the `wpa_supplicant` service:

```
sudo su -
service wpa_supplicant restart
```

As of now the wifi is working perfectly. I have not yet rebooted. I notice that the wifi indicator panel in XFCE still says "WiFi Networks device not managed", but I think that's because it's checking with `NetworkManager`, which is not being used.


## Other nonsense

Much random stabbing in the dark was involved, including the following, I have little idea if these were necessary but this is what Google led me to do:

```
rfkill unblock wifi
systemctl disable systemd-networkd-wait-online.service
systemctl mask systemd-networkd-wait-online.service
```

Useful stuff for debugging:

```
root@at420:~# service netplan-wpa@wlp3s0 status
● netplan-wpa@wlp3s0.service - WPA supplicant for netplan wlp3s0
   Loaded: loaded (/lib/systemd/system/netplan-wpa@.service; indirect; vendor preset: enabled)
   Active: active (running) since Sat 2018-06-30 11:41:10 BST; 32min ago
 Main PID: 2971 (wpa_supplicant)
    Tasks: 1 (limit: 4390)
   CGroup: /system.slice/system-netplan\x2dwpa.slice/netplan-wpa@wlp3s0.service
           └─2971 /sbin/wpa_supplicant -c /run/netplan/wpa-wlp3s0.conf -iwlp3s0

Jun 30 11:41:10 t420 systemd[1]: Started WPA supplicant for netplan wlp3s0.
Jun 30 11:41:10 t420 wpa_supplicant[2971]: Successfully initialized wpa_supplicant
Jun 30 11:41:14 t420 wpa_supplicant[2971]: wlp3s0: SME: Trying to authenticate with 71:5F:58:2F:79:97 (SSID='<my wifi>' freq=2412 MHz)
Jun 30 11:41:14 t420 wpa_supplicant[2971]: wlp3s0: Trying to associate with 71:5F:58:2F:79:97 (SSID='<my wifi>' freq=2412 MHz)
Jun 30 11:41:14 t420 wpa_supplicant[2971]: wlp3s0: Associated with 71:5F:58:2F:79:97
Jun 30 11:41:14 t420 wpa_supplicant[2971]: wlp3s0: CTRL-EVENT-SUBNET-STATUS-UPDATE status=0
Jun 30 11:41:14 t420 wpa_supplicant[2971]: wlp3s0: WPA: Key negotiation completed with 71:5F:58:2F:79:97 [PTK=CCMP GTK=TKIP]
Jun 30 11:41:14 t420 wpa_supplicant[2971]: wlp3s0: CTRL-EVENT-CONNECTED - Connection to 71:5F:58:2F:79:97 completed [id=0 id_str=]
```

```
service wpa_supplicant status
● wpa_supplicant.service - WPA supplicant
   Loaded: loaded (/lib/systemd/system/wpa_supplicant.service; enabled; vendor preset: enabled)
   Active: active (running) since Sat 2018-06-30 11:27:51 BST; 49min ago
 Main PID: 1135 (wpa_supplicant)
    Tasks: 1 (limit: 4390)
   CGroup: /system.slice/wpa_supplicant.service
           └─1135 /sbin/wpa_supplicant -u -s -O /run/wpa_supplicant

Jun 30 11:27:50 t420 systemd[1]: Starting WPA supplicant...
Jun 30 11:27:51 t420 wpa_supplicant[1135]: Successfully initialized wpa_supplicant
Jun 30 11:27:51 t420 systemd[1]: Started WPA supplicant.
```