Your Computer on the Network

The concept of computer networks are the physical connections between two different devices. Links can be established through various media, such as copper cables, optical fibers, radio waves or lasers.

Each link is connected with an interface of a device. Each device can have multiple interfaces and thus be connected to multiple links. Through these computers can form a network; a small community of devices that can directly connect to each other.

This model leads to several different layers of networking:

Link layer: Handles the communication between directly connected devices.

Network layer: Handles routing outside of individual networks and the unique addressing of devices beyond a single link layer network.

Application layer: Enables individual programs to connect to each other.

net-tools

For a long time, these commands were widely used to monitor and configure a network in Linux. They obsolete tools and should be replaced by the modern evolution of them but nonetheless important to know just in case they are encountered in documentation or other sources.

• ifconfig: Network interfaces administration. Changes made here are not permanent and will be reset upon restarting the system.

• netstat: Shows network connections, routing and network traffic statistics.

• route: Show / manipulate the IP routing table