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netcat

Introduction​

This cheat sheet provides a quick reference for some common netcat (nc) commands and concepts. netcat is a versatile networking utility for reading from and writing to network connections using TCP or UDP protocols.

netcat Concepts​

Basic Usage​

netcat can be used to establish network connections, listen on ports, and transfer data.

  • Connect to a remote host and port:

    nc hostname port

  • Listen on a specific port for incoming connections:

    nc -l -p port

Data Transfer​

You can use netcat to send and receive data over network connections.

  • Send a file to a remote host:

    nc -q 1 hostname port < file.txt

  • Receive data from a remote host and save it to a file:

    nc -l -p port > received_data.txt

Port Scanning​

netcat can be used for port scanning to check if specific ports are open on a remote host.

  • Perform a basic port scan on a range of ports:
    nc -zv hostname 1-100

Remote Shell​

You can use netcat to create a simple remote shell.

  • On the listening host, start a shell on a specific port:

    nc -l -p port -e /bin/bash

  • On the remote host, connect to the shell:

    nc hostname port

Chat Mode​

netcat can be used for simple chat or communication between two hosts.

  • Host A listens on a specific port:

    nc -l -p port

  • Host B connects to Host A for chat:

    nc HostA_IP port

netcat Command-Line​

  • Connect to a remote host and port:

    nc hostname port

  • Listen on a specific port for incoming connections:

    nc -l -p port

  • Send a file to a remote host:

    nc -q 1 hostname port < file.txt

  • Receive data from a remote host and save it to a file:

    nc -l -p port > received_data.txt

  • Perform a basic port scan on a range of ports:

    nc -zv hostname 1-100

  • Start a shell on a specific port for remote access:

    nc -l -p port -e /bin/bash

  • Connect to a remote shell:

    nc hostname port

  • Start a chat session:

    nc -l -p port

  • Join a chat session:

    nc HostA_IP port

Conclusion​

This cheat sheet covers some common netcat (nc) commands and concepts. netcat is a powerful networking utility that can be used for various tasks such as data transfer, port scanning, remote shells, and more, making it a valuable tool for network administrators and security professionals; refer to the official netcat documentation for more in-depth information and advanced usage.