Linux Networking

Key Components of Networking

Networking in Linux involves several essential components. Here are the 9 key aspects to understand:

Hardware: The physical devices like network interface cards (NICs), switches, routers, and cables that enable network connectivity.
Operating System (OS): The Linux OS provides the software interface and tools for configuring and managing network connections.
NIC/Ethernet/LAN: The Network Interface Card (NIC) facilitates communication over a network using Ethernet or LAN protocols.
IP Address: A unique identifier assigned to devices on a network to enable communication.
Network: A system of interconnected devices that share resources and data.
Private and Public IPs:
- Private IPs: Used within private networks and cannot communicate directly with public IPs.
- Public IPs: Used for communication over the internet and are accessible globally.
NAT (Network Address Translation): Required when a private IP needs to connect to a public IP. NAT translates private IP addresses into a public IP for internet communication.
Routing Table: Maintains paths for directing data packets between networks. It helps determine the next hop for delivering data.
Switches and Routers:
- Switch: Connects devices within the same network.
- Router: Connects devices across different networks.

Essential Linux Networking Commands

Here are some commonly used commands to configure and troubleshoot networking in Linux:

ifconfig: Displays the IP address and network configurations of the system.
- Example:
```
  ifconfig
```
ifconfig [device]: Used to change the IP address and netmask for a specific device.
- Example:
```
  ifconfig enp0s3 192.168.1.10 netmask 255.255.255.0
```
nslookup: Retrieves the IP address of a domain or website.
- Example:
```
  nslookup www.google.com
```
route -n: Displays the routing table.
- Example:
```
  route -n
```
route del -net [destination IP]: Deletes a route to a destination IP.
- Example:
```
  route del -net 192.168.1.0
```
route add -net [destination IP] netmask [netmask] dev [device]: Adds a route to a destination IP.
- Example:
```
  route add -net 10.0.0.0 netmask 255.255.255.0 dev enp0s3
```
ping: Checks the connectivity between your system and another host.
- Example:
```
  ping 8.8.8.8
```

Summary

Understanding Linux networking requires knowledge of both the hardware and software components that make up a network. Key concepts like IP addressing, NAT, and routing are essential for effective communication between devices. Additionally, mastering basic commands such as ifconfig, route, and ping is crucial for configuring and troubleshooting networks. This documentation serves as a starting point for working with networking in Linux.