What is a "Netstat" command, Give me some examples and how it is helpful for IT Admins?

Date: THURSDAY, 25th June 2024 

Time: 5:30 PM to 6:00 PM

Topic 6:  netstat

Software: Windows Command Line, Linux/Chromebook Crosh Shell

The "netstat" (network statistics) command is a powerful networking tool that provides valuable information about network connections, routing tables, and interface statistics. It's particularly useful for IT administrators in several ways:

1. View active network connections:

Netstat displays all active TCP connections, showing local and foreign addresses, connection states, and associated processes.

Example:

netstat -an

This command shows all connections (-a) with numerical addresses (-n).

2. Monitor open ports:

IT admins can use netstat to list all TCP and UDP ports that are open and listening for incoming connections.

Example:

netstat -tuln

This displays listening TCP (-t) and UDP (-u) ports with numerical addresses (-n).

3. Troubleshoot network issues:

By showing connection states and statistics, netstat helps identify problems like failed connections or unusual network activity.

Example:

netstat -s

This command displays detailed network statistics for various protocols.

4. Identify running processes:

With certain options, netstat can show which executables are responsible for each connection.

Example (Linux):

netstat -p

This shows the PID and program name for each connection.

5. View routing tables:

Netstat can display the IP routing table, which is useful for diagnosing routing issues.

Example:

netstat -r

This command shows the kernel routing table.

6. Check network interface statistics:

IT admins can use netstat to view statistics on network interfaces, including packets sent/received and errors.

Example:

netstat -i

This displays network interface statistics.

7. Monitor specific ports:

Netstat can be used to check if specific ports are in use, which is helpful for troubleshooting server applications.

Example:

netstat -an | grep ':80'

This command checks for connections on port 80 (typically used for web servers).

8. Continuous monitoring:

Netstat can provide ongoing updates, allowing admins to monitor network activity in real-time.

Example:

netstat -c

This continuously updates the netstat information at regular intervals.

Netstat is available on Windows, Linux, and macOS, making it a versatile tool for cross-platform network administration. Its command-line interface allows for easy integration into scripts for automated monitoring and reporting. By providing detailed insights into network connections, open ports, and traffic statistics, netstat enables IT administrators to effectively diagnose issues, monitor network health, and ensure optimal system performance.