eth0 is the first Ethernet interface. (Additional Ethernet interfaces would be named eth1, eth2, etc.) This type of interface is usually a NIC connected to the network by a category 5 cable. lo is the loopback interface. This is a special network interface that the system uses to communicate with itself.

What is network interface eth0?

eth0 is a physical interface representing Ethernet network card. It’s used for communication with other computers on the network and on the Internet. lo is a special virtual network interface called loopback device.

What is eth0 and wlan0?

Eth0 and wlan0 are not assigned by your ip, eth0 and wlan0 are device names assigned by ubuntu. Eth0 is your ehternet connection and wlan0 is your wireless connection but sometimes wlan0 might be called eth1 instead it all depends on the driver your wireless card is using.