What does the 'nc -l 12345' command do?

The command nc -l 12345 is used to start Netcat in listening mode on port 12345. Here's a breakdown of the command:

• nc: This is the command to invoke Netcat.
• -l: This option tells Netcat to listen for incoming connections rather than initiating a connection to a remote host.
• 12345: This specifies the port number on which Netcat will listen for incoming connections.

What Happens When You Run This Command:

1. Listening for Connections: Netcat will wait for a client to connect to port 12345 on the local machine.
2. Data Transfer: Once a client connects, any data sent from the client will be displayed in the terminal where the command is running. Similarly, any data typed into this terminal will be sent to the client.
3. Persistent Connection: The connection will remain open until either the client disconnects or the listening terminal is closed.

This command is useful for testing network connections, debugging, or setting up simple communication channels between two systems.