DHCP (Dynamic Host Configuration Protocol) is a network protocol used by client computers to assign an IP address automatically. If there is a valid configuration in /etc/network/interfaces file and there is a DHCP server or a router in your LAN, an IP address will be assigned to you during system boot. But if the network card is down or we don't have a valid configuration in /etc/network/interfaces file on system boot, we can assign manually an IP address.
- eth0 is the network card the IP address will be assign to
If everything worked, no message will be displayed. To list our new IP address, we need to run ifconfig eth0.