Linux `netstat` Command

In the realm of Linux and network administration, understanding network connections, routing, and networking statistics is vital for managing and troubleshooting network-related issues. The netstat (network statistics) command is a powerful and versatile tool that allows users to display network connections, routing tables, and network interface statistics. In this blog post, we will delve into the netstat command, exploring its syntax, options, practical applications, and understanding how it aids in managing network connections.

Basic Syntax

The basic syntax of the netstat command is:

bash
netstat options

options: Additional flags that modify the behavior of the netstat command.

Displaying Network Connections

To display a list of all active network connections, you can use the netstat command without any options.

bash
netstat

This will display a list of all active connections, including the protocol used, local and foreign addresses, and the status of each connection.

Displaying Routing Table

To display the routing table, you can use the -r or --route option.

bash
netstat -r

This will display the routing table, which shows the routing path for outgoing network packets.

Displaying Network Interface Statistics

To display statistics for network interfaces, you can use the -i or --interfaces option.

bash
netstat -i

This will display statistics for each network interface, including received and transmitted packets, errors, and more.

Practical Applications

Viewing Network Connections:
```
bash
netstat
```
Displaying Routing Table:
```
bash
netstat -r
```
Displaying Interface Statistics:
```
bash
netstat -i
```

Understanding the Output

The output of the netstat command includes vital information about network connections, routing tables, and network interface statistics. Understanding this information is crucial for managing network connectivity, diagnosing network issues, and optimizing network performance.

Advanced Usage

Displaying Listening Ports

You can use the -l or --listening option to display only listening ports.

bash
netstat -l

Displaying Numerical Addresses

To display numerical addresses instead of resolving hostnames, you can use the -n or --numeric option.

bash
netstat -n

Displaying All Sockets

To display all sockets, including listening and non-listening sockets, you can use the -a or --all option.

bash
netstat -a

Linux netstat Command