You will learn how to identify essential network addressing information on a Linux system using the modern and powerful ip a command. The primary goal is to become proficient at inspecting your system's network interfaces and locating specific details within the command's output, including MAC addresses, IPv4 addresses, and IPv6 addresses.
Start by executing the ip a command to display a comprehensive overview of all network interfaces, such as the loopback (lo) and primary Ethernet (eth0) interfaces. Following this, you will learn to parse the detailed output to pinpoint the link/ether line for the MAC address, the inet line for the IPv4 address, and the inet6 line for the IPv6 address, solidifying your understanding of fundamental Linux network analysis.
lo: This is the loopback interface, a virtual network interface that the system uses to communicate with itself. It always has the IP address 127.0.0.1.
eth0 (or a similar name like enp0s5): This is your primary Ethernet interface, which connects your system to the external network. Notice the altname fields, which provide alternative names for the interface.
docker0: If Docker is installed, you might see a docker0 interface, which is a virtual bridge created by Docker for container networking.