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

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(Broadcom Wi-Fi Chipset Users: this should be aports now, not abuild)
(Separate manual from automatic configuration and add more detail for less experienced users.)
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This document describes how to set up a wireless network connection with WPA encryption.
 
This document describes how to set up a wireless network connection with WPA encryption.
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 +
== Install necessary drivers and software  ==
  
 
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]].)
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Install {{Pkg|wireless-tools}} and {{Pkg|wpa_supplicant}}.
 
Install {{Pkg|wireless-tools}} and {{Pkg|wpa_supplicant}}.
 
{{Cmd|apk add wireless-tools wpa_supplicant}}
 
{{Cmd|apk add wireless-tools wpa_supplicant}}
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 +
== Manual Configuration  ==
  
 
Bring the link up so we can look for wireless networks. (An error here means you probably need extra drivers/firmware.)
 
Bring the link up so we can look for wireless networks. (An error here means you probably need extra drivers/firmware.)
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{{Cmd|iwlist wlan0 scanning}}
 
{{Cmd|iwlist wlan0 scanning}}
  
Let's set the ESSID:
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Configure the wlan0 interface to associate with the MyNet ESSID:
 
{{Cmd|iwconfig wlan0 essid MyNet}}
 
{{Cmd|iwconfig wlan0 essid MyNet}}
  
We need to create a shared key for wpa_supplicant.
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Print its configuration, to check:
{{Cmd|wpa_passphrase MyNet > wpa.conf}}
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{{Cmd|iwconfig wlan0}}
It will wait for the password from stdin. Enter the password and enter. Now you will have a {{Path|wpa.conf}} file with the preshared key.
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Create a wpa_supplicant configuration stanza for wpa_supplicant by executing the following:
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{{Cmd|wpa_passphrase MyNet > wpa.conf}}
  
Start wpa_supplicant with the generated config:
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wpa_passphrase expects the password to be passed via stdin. 
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 +
So, type the password and press ENTER.
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 +
The above commands creates the file {{Path|wpa.conf}} which includes the pre-shared key. 
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 +
From one terminal/console, start wpa_supplicant with the generated config:
 
{{Cmd|wpa_supplicant -Dwext -iwlan0 -c ./wpa.conf}}
 
{{Cmd|wpa_supplicant -Dwext -iwlan0 -c ./wpa.conf}}
  
From another console, start dhcpcd:
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From another terminal/console, start dhcpcd:
 
{{Cmd|udhcpc -i wlan0}}
 
{{Cmd|udhcpc -i wlan0}}
  
You should get an IP address.
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The wlan0 interface should be configured with an IP address at this point:
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{{Cmd|ifconfig wlan0}}
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== Automatic Configuration on System Boot  ==
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 +
Add an interface stanza for wlan0 to the file {{Path|/etc/network/interfaces}}
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 +
<pre>
 +
auto wlan0
 +
iface wlan0 inet dhcp
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</pre>
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 +
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}}.
 +
 
 +
<pre>
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mkdir -p /etc/wpa_supplicant
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chmod 750 /etc/wpa_supplicant
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cat wpa.conf >> /etc/wpa_supplicant/wpa_supplicant.conf
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</pre>
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 +
Test the automatic interface configuration:
 +
 
 +
Bring the interface down:
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 +
{{Cmd|ifconfig wlan0 down}}
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 +
Manually start wpa_supplicant
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 +
{{Cmd|/etc/init.d/wpa_supplicant start}}
  
You then want to make the connection process automatic on boot-up.  Open {{Path|/etc/network/interfaces}} and add the following stanza:
+
The wlan0 interface should be associated with the MyNet SSID:
auto wlan0
+
 
iface wlan0 inet dhcp
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{{Cmd|iwconfig wlan0}}
{{Note|I had to append `pre-up iwconfig wlan0 essid <ESSID>` to automatically connect to the network.}}
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 +
The wlan0 interface should have been assigned an IP address via DHCP:
 +
 
 +
{{Cmd|ifconfig wlan0}}
 +
 
 +
Configure wpa_supplicant to start automatically on boot:
  
You will also need to set wpa_supplicant to start automatically on boot:
 
 
{{Cmd|rc-update add wpa_supplicant boot}}
 
{{Cmd|rc-update add wpa_supplicant boot}}
  
Next, create {{Path|/etc/wpa_supplicant/}} (permissions of 755 with root:root are fine), and move {{Path|wpa.conf}} into that folder, renaming it to {{Path|wpa_supplicant.conf}}.
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Reboot:
 +
 
 +
{{Cmd|reboot}}
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 +
Log in and check that the interface is associated with the access point:
  
Reboot and check that you are associated with the access point:
 
 
{{Cmd|iwconfig wlan0}}
 
{{Cmd|iwconfig wlan0}}
and check that you got a DHCP lease:
+
 
 +
Check that the interface was assigned an IP address via DHCP:
 +
 
 
{{Cmd|ifconfig wlan0 {{!}} grep addr}}
 
{{Cmd|ifconfig wlan0 {{!}} grep addr}}
  
 
== Broadcom Wi-Fi Chipset Users  ==
 
== 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.  
 
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.  
  

Revision as of 10:05, 21 November 2017

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.

apk add wireless-tools wpa_supplicant

Manual Configuration

Bring the link up so we can look for wireless networks. (An error here means you probably need extra drivers/firmware.)

ip link set wlan0 up

Find a network to connect to. Look for the ESSID. In this example we will use the ESSID "MyNet".

iwlist wlan0 scanning

Configure the wlan0 interface to associate with the MyNet ESSID:

iwconfig wlan0 essid MyNet

Print its configuration, to check:

iwconfig wlan0

Create a wpa_supplicant configuration stanza for wpa_supplicant by executing the following:

wpa_passphrase MyNet > wpa.conf

wpa_passphrase expects the password to be passed via stdin.

So, type the password and press ENTER.

The above commands creates the file wpa.conf which includes the pre-shared key.

From one terminal/console, start wpa_supplicant with the generated config:

wpa_supplicant -Dwext -iwlan0 -c ./wpa.conf

From another terminal/console, start dhcpcd:

udhcpc -i wlan0

The wlan0 interface should be configured with an IP address at this point:

ifconfig wlan0

Automatic Configuration on System Boot

Add an interface stanza for wlan0 to the file /etc/network/interfaces

auto wlan0
iface wlan0 inet dhcp

Create /etc/wpa_supplicant if it doesn't already exist, set sane permissions and append the configuration wpa.conf to wpa_supplicant.conf.

mkdir -p /etc/wpa_supplicant
chmod 750 /etc/wpa_supplicant
cat wpa.conf >> /etc/wpa_supplicant/wpa_supplicant.conf

Test the automatic interface configuration:

Bring the interface down:

ifconfig wlan0 down

Manually start wpa_supplicant

/etc/init.d/wpa_supplicant start

The wlan0 interface should be associated with the MyNet SSID:

iwconfig wlan0

The wlan0 interface should have been assigned an IP address via DHCP:

ifconfig wlan0

Configure wpa_supplicant to start automatically on boot:

rc-update add wpa_supplicant boot

Reboot:

reboot

Log in and check that the interface is associated with the access point:

iwconfig wlan0

Check that the interface was assigned an IP address via DHCP:

ifconfig wlan0 | grep addr

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 an 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.

You can't be root and must be a user of the group abuild (use groupadd)

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.