WPA2 Without Network Manager

This shows how to configure roaming with WPA2-encrypted WLAN networks. The following is my adaption of https://zivwiki.uni-muenster.de/bin/view/Anleitungen/WirelessLANSetupDebian#3_WPA_configuration_for_roaming.

/etc/network/interfaces (ath1 is the wlan interface, some_essid and another_essid are “virtual interfaces” defined in /etc/wpa_supplicant/roam.conf):

auto lo
iface lo inet loopback

auto ath1
allow-hotplug ath1
iface ath1 inet manual
    wpa-driver wext
    wpa-roam /etc/wpa_supplicant/roam.conf

iface home inet dhcp
iface uni inet dhcp

/etc/wpa_supplicant/roam.conf:

ctrl_interface=/var/run/wpa_supplicant
ctrl_interface_group=0
ap_scan=1
fast_reauth=1
eapol_version=1
network={
    id_str="home"
    ssid=<essid of my router>
    psk=<wpa_passphrase-generated-key>
    priority=5
}
network={
    id_str="uni"
    ssid=<essid of the university's router>
    psk=<wpa_passphrase-generated-key>
    priority=3
}

Some Hints

Manual control:

ifup ath1  # brings up the pysical interface while redirecting control to wpa_supplicant
wpa_cli  # type help or status...
wpa_action home stop
wpa_action uni reload
# ...