Displaying network connections in the Windows Command Prompt (cmd) is crucial for monitoring the status of your network, identifying active connections, and diagnosing potential issues. You can use various commands to view details about current network connections, open ports, and their respective states. Below, I’ll explain some of the most commonly used commands for displaying network connections, along with examples and expected outputs.

1. Using the netstat Command

The netstat (Network Statistics) command provides detailed information about current network connections, including protocol, local and remote addresses, port numbers, and the status of each connection.

Basic Syntax:

netstat

Example:

To view all current network connections, enter:

netstat

Output:

C:\Users\YourUsername>netstat

Proto  Local Address          Foreign Address        State
TCP    192.168.1.10:49152    google.com:80         ESTABLISHED
TCP    192.168.1.10:49153    example.com:443       TIME_WAIT
TCP    192.168.1.10:49154    203.0.113.45:23       CLOSE_WAIT
UDP    192.168.1.10:5353     *:*                   

Output Explanation:

• Proto: The protocol used (TCP or UDP).
• Local Address: The local IP address and port number of the connection.
• Foreign Address: The remote IP address and port number of the connection.
• State: The current state of the TCP connection (e.g., ESTABLISHED, TIME_WAIT, CLOSE_WAIT).

2. Using the netstat -a Command

The -a option shows all active connections and listening ports.

Example:

To display all active connections and listening ports, enter:

netstat -a

Output:

C:\Users\YourUsername>netstat -a

Proto  Local Address          Foreign Address        State
TCP    192.168.1.10:49152    google.com:80         ESTABLISHED
TCP    192.168.1.10:49153    example.com:443       TIME_WAIT
TCP    192.168.1.10:49154    203.0.113.45:23       CLOSE_WAIT
TCP    192.168.1.10:49155    *:80                   LISTENING
UDP    192.168.1.10:5353     *:*                    

3. Using the netstat -n Command

The -n option displays addresses and port numbers in numerical form, which can be faster since it avoids resolving hostnames.

Example:

To show connections without resolving hostnames, enter:

netstat -n

Output:

C:\Users\YourUsername>netstat -n

Proto  Local Address          Foreign Address        State
TCP    192.168.1.10:49152    172.217.6.206:80      ESTABLISHED
TCP    192.168.1.10:49153    203.0.113.45:443      TIME_WAIT
UDP    192.168.1.10:5353     0.0.0.0:0             

4. Using the netstat -o Command

The -o option displays the Process ID (PID) associated with each connection, allowing you to identify which application is using the connection.

Example:

To show connections with their associated PIDs, enter:

netstat -o

Output:

C:\Users\YourUsername>netstat -o

Proto  Local Address          Foreign Address        State           PID
TCP    192.168.1.10:49152    google.com:80         ESTABLISHED     1234
TCP    192.168.1.10:49153    example.com:443       TIME_WAIT       5678

5. Using the netstat -p Command

You can specify a protocol with the -p option to filter the connections. For example, to view only TCP connections, use:

Example:

netstat -p tcp

Output:

C:\Users\YourUsername>netstat -p tcp

Proto  Local Address          Foreign Address        State
TCP    192.168.1.10:49152    google.com:80         ESTABLISHED

6. Using the tasklist Command

You can also use the tasklist command to see a list of running processes, which can be useful in conjunction with the netstat -o command to identify which application is using a specific port.

Example:

To view the list of currently running processes, enter:

tasklist

Output:

C:\Users\YourUsername>tasklist

Image Name                     PID Session Name        Session#    Mem Usage
========================= ======== ================ =========== ============
System Idle Process              0 Services                   0         28 K
System                           4 Services                   0        376 K
smss.exe                      484 Services                   0        224 K
csrss.exe                     576 Console                    1      1,024 K
wininit.exe                   660 Services                   0        544 K

Summary

Displaying network connections in the Windows Command Prompt can be accomplished using various commands, such as netstat, which provides detailed information about active connections, listening ports, and associated process IDs. By combining these commands, you can effectively monitor your network activity, identify potential issues, and troubleshoot network connectivity problems. Understanding how to use these commands is essential for network management and security.