How to setup a wireless access point

This material is work-in-progress ... Do not follow instructions here until this notice is removed. (Last edited by Pojntfx on 3 Aug 2020.)

Install needed packages

apk add bridge hostapd wireless-tools wpa_supplicant

Check that card is detected

Cat /proc/net/dev and see which cards are detected. If no cards are available, check what driver the card uses and modprobe it. Check that the card is in master mode.

Setup Bridge

Setup the bridge by editing /etc/network/interfaces. Assuming that you wish to bridge the access point to the ethernet device eth0, you can add something like this:

auto br0
iface br0 inet dhcp
  hostname alpine
  bridge-ports eth0

Comment out any existing lines configuring eth0 as this should now be handled via the bridge configuration. It is not necessary to mention wlan0 here, as hostapd will take care of adding the device to the bridge later.

Please see Bridge for more information on network bridges.

Setup Encryption

Edit /etc/hostapd/hostapd.wpa_psk and insert the following, replacing PASSPHRASE with the WPA_PSK key you would like to use (remove keys that you don't want to use):

00:00:00:00:00:00 PASSPHRASE

Setup hostapd

Edit /etc/hostapd/hostapd.conf and replace entries that need to be such as interface, bridge, driver, ssid, etc. Example file below:

interface=wlan0
bridge=br0
driver=hostap
logger_syslog=-1
logger_syslog_level=2
logger_stdout=-1
logger_stdout_level=2
debug=0
dump_file=/tmp/hostapd.dump
ctrl_interface=/var/run/hostapd
ctrl_interface_group=0
ssid=SecureSSID
#macaddr_acl=1
#accept_mac_file=/etc/hostapd/accept
auth_algs=3
eapol_key_index_workaround=0
eap_server=0
wpa=3
wpa_psk_file=/etc/hostapd/hostapd.wpa_psk
wpa_key_mgmt=WPA-PSK
wpa_pairwise=CCMP

If you wish to use MAC address filtering, uncomment the lines starting with macaddr_acl and accept_mac_file, create /etc/hostapd/accept (with 600 permissions) and add the allowed clients' MAC address to the file.

Start hostapd.

/etc/init.d/hostapd start

Associate clients

Associate a few different clients to test.

See also

• Wireless AP with udhcpd and NAT
• Raspberry Pi 3 - Configuring it as wireless access point -AP Mode