11.6.2 How to Set up Static IP Address in Raspberry Pi
The default setting for the IP address in the Raspberry Pi system is stored in “/etc/network/interfaces” file. Normally, the contents as follows are stored.
iface lo inet lookback
iface eth0 inet dhcp
iface wlan0 inet dhcp
wpa-ssid “wifissid”
wpa-psk “wifipassword”