Listening with Netcat

• With a netcat listener on one host, and netcat on another, you can send data, files, or anything from one host to another across any TCP/IP port.

TCP listeners

• Use the –l flag to tell netcat to listen. Here is shown how you can create a network socket on TCP port 9999.
  • nc –l 9999

UDP Listeners

• Here’s a netcat listener on UDP port 8888.
  • nc –ul 8888
• Netcat displays exactly what it receives. Real applications that use UDP implement their own error correction.

Sending Files with Netcat

• The contents of any data stream sent to TCP port 9999 will get sent to the specified file.
  • nc –l 9999 > received_file