netstat and ss (connection listing) in Linux CLI - Mini Project: Build & Apply

Listing Network Connections with netstat and ss

📖 Scenario: You are a system administrator who needs to check active network connections on a Linux server. You want to list all current TCP connections and see which ports are listening for incoming connections.

🎯 Goal: Learn how to use netstat and ss commands to list active network connections and listening ports.

📋 What You'll Learn

Use netstat to list all TCP connections

Use ss to list all listening TCP ports

Filter output to show only established connections or listening ports

Display the final output clearly

💡 Why This Matters

🌍 Real World

System administrators often need to check active network connections to troubleshoot network issues or monitor server activity.

💼 Career

Knowing how to use <code>netstat</code> and <code>ss</code> is essential for Linux system administrators and network engineers.

1

List all TCP connections using netstat

Type the command netstat -tn to list all current TCP connections with numeric addresses.

Linux CLI

# Type the command netstat -tn to list TCP connections
# Your code here

Need a hint?

The -t option shows TCP connections and -n shows numeric addresses.

2

List all listening TCP ports using ss

Type the command ss -lt to list all listening TCP ports.

Linux CLI

netstat -tn
# Type the command ss -lt to list listening TCP ports
# Your code here

Need a hint?

The -l option shows listening sockets and -t limits to TCP.

3

Filter netstat output to show only established TCP connections

Type the command netstat -tn | grep ESTABLISHED to show only established TCP connections.

Linux CLI

netstat -tn
ss -lt
# Filter netstat output to show only ESTABLISHED connections
# Your code here

Need a hint?

Use grep ESTABLISHED to filter connections in the ESTABLISHED state.

4

Display listening TCP ports with detailed info using ss

Type the command ss -ltp to list listening TCP ports with the process info.

Linux CLI

netstat -tn
ss -lt
netstat -tn | grep ESTABLISHED
# Type ss -ltp to show listening TCP ports with process info
# Your code here

Need a hint?

The -p option shows the process using the socket.