Difference between revisions of "Connecting to a wireless access point"

From Alpine Linux
Jump to: navigation, search
(Separate manual from automatic configuration and add more detail for less experienced users.)
 
(21 intermediate revisions by 9 users not shown)
Line 5: Line 5:
 
First make sure your wireless drivers are loaded properly. (if you are using a '''Broadcom chipset''', see the [[#Broadcom_Wi-Fi_Chipset_Users|section at the bottom of this post]].)
 
First make sure your wireless drivers are loaded properly. (if you are using a '''Broadcom chipset''', see the [[#Broadcom_Wi-Fi_Chipset_Users|section at the bottom of this post]].)
  
Install {{Pkg|wireless-tools}} and {{Pkg|wpa_supplicant}}.
+
Install {{Pkg|wireless-tools}} and {{Pkg|wpa_supplicant}}, which are probably available to be installed in the base setup.
 
{{Cmd|apk add wireless-tools wpa_supplicant}}
 
{{Cmd|apk add wireless-tools wpa_supplicant}}
  
 
== Manual Configuration  ==
 
== Manual Configuration  ==
  
Bring the link up so we can look for wireless networks. (An error here means you probably need extra drivers/firmware.)
+
List your available network interfaces. If you don't see any wireless interfaces (e.g. {{Path|wlan0}}), you probably need to load and/or install drivers/firmware.
 +
{{Cmd|ip link}}
 +
 
 +
Bring up the desired interface.
 
{{Cmd|ip link set wlan0 up}}
 
{{Cmd|ip link set wlan0 up}}
  
Find a network to connect to. Look for the ESSID. In this example we will use the ESSID "MyNet".
+
{{Note|If this errors with <code>ioctl 0x8914 failed: No error information</code>, that's <code>busybox ip</code>'s way of saying your wireless radio is rfkill'd. See [https://wiki.archlinux.org/index.php/Wireless_network_configuration#Rfkill_caveat here] for information on how to unblock your wireless radio.
 +
The base installation should have <code>busybox rfkill</code> available.}}
 +
 
 +
 
 +
Use the interface to scan for wireless access points. Make sure the ESSID you want to connect to appears here.
 
{{Cmd|iwlist wlan0 scanning}}
 
{{Cmd|iwlist wlan0 scanning}}
  
Configure the wlan0 interface to associate with the MyNet ESSID:
+
Associate the interface with desired ESSID.
{{Cmd|iwconfig wlan0 essid MyNet}}
+
{{Cmd|iwconfig wlan0 essid ExampleWifi}}
  
Print its configuration, to check:
+
Sanity check: the interface should be configured with {{Path|ESSID:"ExampleWifi"}}.
 
{{Cmd|iwconfig wlan0}}
 
{{Cmd|iwconfig wlan0}}
  
Create a wpa_supplicant configuration stanza for wpa_supplicant by executing the following:
+
Create a wpa_supplicant configuration stanza for the wireless access point.
{{Cmd|wpa_passphrase MyNet > wpa.conf}}
+
{{Cmd|wpa_passphrase 'ExampleWifi' 'ExampleWifiPassword' > /etc/wpa_supplicant/wpa_supplicant.conf}}
 +
''(Access point not broadcasting its SSID requires additional line <code>scan_ssid=1</code> in the file <code>wpa_supplicant.conf</code>)''
  
wpa_passphrase expects the password to be passed via stdin. 
 
  
So, type the password and press ENTER.
+
Start wpa_supplicant in the foreground to make sure the connection succeeds.
+
{{Cmd|wpa_supplicant -i wlan0 -c /etc/wpa_supplicant/wpa_supplicant.conf}}
The above commands creates the file {{Path|wpa.conf}} which includes the pre-shared key. 
 
  
From one terminal/console, start wpa_supplicant with the generated config:
+
If all is well, run it as a daemon in the background by setting the {{Path|-B}} option.
{{Cmd|wpa_supplicant -Dwext -iwlan0 -c ./wpa.conf}}
+
{{Cmd|wpa_supplicant -B -i wlan0 -c /etc/wpa_supplicant/wpa_supplicant.conf}}
  
From another terminal/console, start dhcpcd:
+
Configure the interface with an IP address.
 
{{Cmd|udhcpc -i wlan0}}
 
{{Cmd|udhcpc -i wlan0}}
  
The wlan0 interface should be configured with an IP address at this point:
+
Sanity check: the interface should have an {{Path|inet}} address.
{{Cmd|ifconfig wlan0}}
+
{{Cmd|ip addr show wlan0}}
  
 
== Automatic Configuration on System Boot  ==
 
== Automatic Configuration on System Boot  ==
  
Add an interface stanza for wlan0 to the file {{Path|/etc/network/interfaces}}
+
Add a stanza for the desired interface (e.g. {{Path|wlan0}}) to {{Path|/etc/network/interfaces}}:
  
 
<pre>
 
<pre>
Line 49: Line 55:
 
</pre>
 
</pre>
  
Create {{Path|/etc/wpa_supplicant}} if it doesn't already exist, set sane permissions and append the configuration {{Path|wpa.conf}} to {{Path|wpa_supplicant.conf}}.
+
Make sure {{Path|/etc/wpa_supplicant/wpa_supplicant.conf}} is the correct configuration for the wireless access point you want to connect to.
 
 
<pre>
 
mkdir -p /etc/wpa_supplicant
 
chmod 750 /etc/wpa_supplicant
 
cat wpa.conf >> /etc/wpa_supplicant/wpa_supplicant.conf
 
</pre>
 
 
 
Test the automatic interface configuration:
 
  
Bring the interface down:
+
Bring the interface down.
  
 
{{Cmd|ifconfig wlan0 down}}
 
{{Cmd|ifconfig wlan0 down}}
  
Manually start wpa_supplicant
+
Manually start wpa_supplicant.
  
 
{{Cmd|/etc/init.d/wpa_supplicant start}}
 
{{Cmd|/etc/init.d/wpa_supplicant start}}
  
The wlan0 interface should be associated with the MyNet SSID:
+
If all is well (confirm with the sanity checks in [[#Manual_Configuration|Manual Configuration]]), configure wpa_supplicant to start automatically on boot.
  
{{Cmd|iwconfig wlan0}}
+
{{Cmd|rc-update add wpa_supplicant boot}}
 
 
The wlan0 interface should have been assigned an IP address via DHCP:
 
  
{{Cmd|ifconfig wlan0}}
 
  
Configure wpa_supplicant to start automatically on boot:
+
=== Launching udhcpc through wpa_cli actions ===
  
{{Cmd|rc-update add wpa_supplicant boot}}
+
With the above configuration, udhcpc will only run once at boot.
 +
If the Wifi isn't available then, or the network changes in between, it needs to be notified.
 +
This is done through the wpa_cli action script in /etc/wpa_supplicant/wpa_cli.sh
  
Reboot:
+
== Automatic Reconnection when WIFI signal is lost  ==
 +
To enable automatic reconnection when wifi signal is lost add these to config:
  
{{Cmd|reboot}}
+
{{Cat|/etc/wpa_supplicant/wpa_supplicant.conf|
 
+
<nowiki>
Log in and check that the interface is associated with the access point:
+
ap_scan=1
 
+
autoscan=periodic:10
{{Cmd|iwconfig wlan0}}
+
disable_scan_offload=1
 +
</nowiki>
 +
}}
  
Check that the interface was assigned an IP address via DHCP:
 
  
{{Cmd|ifconfig wlan0 {{!}} grep addr}}
+
{{Cmd|rc-update add wpa_cli boot}}
  
 
== Broadcom Wi-Fi Chipset Users  ==
 
== Broadcom Wi-Fi Chipset Users  ==
Line 99: Line 98:
 
{{Cmd|dmesg {{!}} grep Broadcom}}
 
{{Cmd|dmesg {{!}} grep Broadcom}}
  
First install the SDK an Git:
+
First install the SDK and Git:
 
{{Cmd|apk add alpine-sdk git}}
 
{{Cmd|apk add alpine-sdk git}}
  
Line 109: Line 108:
 
Change your directory to '''aports/non-free/b43-firmware''', then build it.
 
Change your directory to '''aports/non-free/b43-firmware''', then build it.
  
''You can't be root and must be a user of the group abuild (use groupadd)''
+
{{Tip|You can't be root and must be a user of the group abuild (use groupadd f.e. '''addgroup $(whoami) abuild''')}}
 +
{{Tip|If this is your first time building a package you will need to generate a key for use in signing packages (use '''abuild-keygen -a -i''')}}
  
 
{{Cmd|abuild -r}}
 
{{Cmd|abuild -r}}

Latest revision as of 15:11, 6 October 2021

This document describes how to set up a wireless network connection with WPA encryption.

Install necessary drivers and software

First make sure your wireless drivers are loaded properly. (if you are using a Broadcom chipset, see the section at the bottom of this post.)

Install wireless-tools and wpa_supplicant, which are probably available to be installed in the base setup.

apk add wireless-tools wpa_supplicant

Manual Configuration

List your available network interfaces. If you don't see any wireless interfaces (e.g. wlan0), you probably need to load and/or install drivers/firmware.

ip link

Bring up the desired interface.

ip link set wlan0 up

Note: If this errors with ioctl 0x8914 failed: No error information, that's busybox ip's way of saying your wireless radio is rfkill'd. See here for information on how to unblock your wireless radio. The base installation should have busybox rfkill available.


Use the interface to scan for wireless access points. Make sure the ESSID you want to connect to appears here.

iwlist wlan0 scanning

Associate the interface with desired ESSID.

iwconfig wlan0 essid ExampleWifi

Sanity check: the interface should be configured with ESSID:"ExampleWifi".

iwconfig wlan0

Create a wpa_supplicant configuration stanza for the wireless access point.

wpa_passphrase 'ExampleWifi' 'ExampleWifiPassword' > /etc/wpa_supplicant/wpa_supplicant.conf

(Access point not broadcasting its SSID requires additional line scan_ssid=1 in the file wpa_supplicant.conf)


Start wpa_supplicant in the foreground to make sure the connection succeeds.

wpa_supplicant -i wlan0 -c /etc/wpa_supplicant/wpa_supplicant.conf

If all is well, run it as a daemon in the background by setting the -B option.

wpa_supplicant -B -i wlan0 -c /etc/wpa_supplicant/wpa_supplicant.conf

Configure the interface with an IP address.

udhcpc -i wlan0

Sanity check: the interface should have an inet address.

ip addr show wlan0

Automatic Configuration on System Boot

Add a stanza for the desired interface (e.g. wlan0) to /etc/network/interfaces:

auto wlan0
iface wlan0 inet dhcp

Make sure /etc/wpa_supplicant/wpa_supplicant.conf is the correct configuration for the wireless access point you want to connect to.

Bring the interface down.

ifconfig wlan0 down

Manually start wpa_supplicant.

/etc/init.d/wpa_supplicant start

If all is well (confirm with the sanity checks in Manual Configuration), configure wpa_supplicant to start automatically on boot.

rc-update add wpa_supplicant boot


Launching udhcpc through wpa_cli actions

With the above configuration, udhcpc will only run once at boot. If the Wifi isn't available then, or the network changes in between, it needs to be notified. This is done through the wpa_cli action script in /etc/wpa_supplicant/wpa_cli.sh

Automatic Reconnection when WIFI signal is lost

To enable automatic reconnection when wifi signal is lost add these to config:

Contents of /etc/wpa_supplicant/wpa_supplicant.conf

ap_scan=1 autoscan=periodic:10 disable_scan_offload=1


rc-update add wpa_cli boot

Broadcom Wi-Fi Chipset Users

The Broadcom chipset is quite popular among older computers. You will need to compile the firmware manually for this chipset as it is not included.

You can check if you have a Broadcom chipset by using dmesg:

dmesg | grep Broadcom

First install the SDK and Git:

apk add alpine-sdk git

Then git clone aports from git.alpinelinux.org.


git clone git://git.alpinelinux.org/aports

Change your directory to aports/non-free/b43-firmware, then build it.

Tip: You can't be root and must be a user of the group abuild (use groupadd f.e. addgroup $(whoami) abuild)
Tip: If this is your first time building a package you will need to generate a key for use in signing packages (use abuild-keygen -a -i)

abuild -r

Install the generated packge file (it will be in ~/packages/) - make sure to pass --allow-untrusted

apk add --allow-untrusted ~/packages/...pkg

Now we need fwcutter, which is executed from the firmware package:

apk add b43-fwcutter b43-firmware

Now you need to use modprobe so the device will show up:

modprobe b43

To automate this on startup add it to /etc/modules:

echo b43 >> /etc/modules

Now continue with the normal instructions.