/etc/network/interfaces: Debian and Ubuntu Network Configuration File

The '/etc/network/interfaces' file is a configuration file used by the Debian and Ubuntu Linux operating systems to define network interfaces and their associated parameters.

This file contains information about the network devices on the system, such as Ethernet cards, wireless adapters, and virtual interfaces. It also specifies the IP address, netmask, gateway, and DNS servers for each interface.

The format of the file is simple, with each network interface defined on a separate line. Each line contains the name of the interface, followed by its configuration parameters.

For example, a typical '/etc/network/interfaces' file might contain the following lines:

# The primary network interface
auto eth0
iface eth0 inet static
	 address 192.168.1.100
	 netmask 255.255.255.0
	 gateway 192.168.1.1
	 dns-nameservers 8.8.8.8 8.8.4.4

# The loopback network interface
auto lo
iface lo inet loopback

In this example, the first section defines the primary Ethernet interface (eth0) with a static IP address, netmask, gateway, and DNS servers. The second section defines the loopback interface (lo) with the 'loopback' address of 127.0.0.1.

The '/etc/network/interfaces' file is typically edited by system administrators to configure network interfaces on their Linux systems.