wpa_supplicant is configured using a text file that lists all accepted networks and security policies, including pre-shared keys. See the example configuration file, probably in /usr/share/doc/wpa_supplicant/, for detailed information about the configuration format and supported fields.
All file paths in this configuration file should use full (absolute, not relative to working directory) path in order to allow working directory to be changed. This can happen if wpa_supplicant is run in the background.
Changes to configuration file can be reloaded be sending SIGHUP signal to wpa_supplicant ('killall -HUP wpa_supplicant'). Similarly, reloading can be triggered with the wpa_cli reconfigure command.
Configuration file can include one or more network blocks, e.g., one for each used SSID. wpa_supplicant will automatically select the best network based on the order of network blocks in the configuration file, network security level (WPA/WPA2 is preferred), and signal strength.
# allow frontend (e.g., wpa_cli) to be used by all users in 'wheel' group ctrl_interface=DIR=/var/run/wpa_supplicant GROUP=wheel # # home network; allow all valid ciphers network={ ssid="home" scan_ssid=1 key_mgmt=WPA-PSK psk="very secret passphrase" } # # work network; use EAP-TLS with WPA; allow only CCMP and TKIP ciphers network={ ssid="work" scan_ssid=1 key_mgmt=WPA-EAP pairwise=CCMP TKIP group=CCMP TKIP eap=TLS identity="user@example.com" ca_cert="/etc/cert/ca.pem" client_cert="/etc/cert/user.pem" private_key="/etc/cert/user.prv" private_key_passwd="password" }
ctrl_interface=DIR=/var/run/wpa_supplicant GROUP=wheel network={ ssid="example" scan_ssid=1 key_mgmt=WPA-EAP eap=PEAP identity="user@example.com" password="foobar" ca_cert="/etc/cert/ca.pem" phase1="peaplabel=0" phase2="auth=MSCHAPV2" }
ctrl_interface=DIR=/var/run/wpa_supplicant GROUP=wheel network={ ssid="example" scan_ssid=1 key_mgmt=WPA-EAP eap=TTLS identity="user@example.com" anonymous_identity="anonymous@example.com" password="foobar" ca_cert="/etc/cert/ca.pem" phase2="auth=MD5" }
ctrl_interface=DIR=/var/run/wpa_supplicant GROUP=wheel network={ ssid="1x-test" scan_ssid=1 key_mgmt=IEEE8021X eap=TLS identity="user@example.com" ca_cert="/etc/cert/ca.pem" client_cert="/etc/cert/user.pem" private_key="/etc/cert/user.prv" private_key_passwd="password" eapol_flags=3 }
ctrl_interface=DIR=/var/run/wpa_supplicant GROUP=wheel network={ ssid="example" scan_ssid=1 key_mgmt=WPA-EAP WPA-PSK IEEE8021X NONE pairwise=CCMP TKIP group=CCMP TKIP WEP104 WEP40 psk="very secret passphrase" eap=TTLS PEAP TLS identity="user@example.com" password="foobar" ca_cert="/etc/cert/ca.pem" client_cert="/etc/cert/user.pem" private_key="/etc/cert/user.prv" private_key_passwd="password" phase1="peaplabel=0" ca_cert2="/etc/cert/ca2.pem" client_cert2="/etc/cer/user.pem" private_key2="/etc/cer/user.prv" private_key2_passwd="password" }
ctrl_interface=DIR=/var/run/wpa_supplicant GROUP=wheel ap_scan=0 network={ key_mgmt=IEEE8021X eap=MD5 identity="user" password="password" eapol_flags=0 }
Some EAP authentication methods require use of certificates. EAP-TLS uses both server side and client certificates whereas EAP-PEAP and EAP-TTLS only require the server side certificate. When client certificate is used, a matching private key file has to also be included in configuration. If the private key uses a passphrase, this has to be configured in wpa_supplicant.conf ("private_key_passwd").
wpa_supplicant supports X.509 certificates in PEM and DER formats. User certificate and private key can be included in the same file.
If the user certificate and private key is received in PKCS#12/PFX format, they need to be converted to suitable PEM/DER format for wpa_supplicant. This can be done, e.g., with following commands:
# convert client certificate and private key to PEM format openssl pkcs12 -in example.pfx -out user.pem -clcerts # convert CA certificate (if included in PFX file) to PEM format openssl pkcs12 -in example.pfx -out ca.pem -cacerts -nokeys
wpa_supplicant(8) openssl(1)