2.20.3.8. NetCat

NetCat (or nc) is a utility that allows you to create TCP and UDP connections. Functionally similar to telnet... Available by default on Unix and macOS, not available on Windows.

Usage

  1. Open terminal on macOS or Linux.
  2. Enter the command and press Enter:
    nc -v example.com 80

    In the team instead of example.com specify the IP or address of the site to which you want to connect (the address must be specified without http:// or https:// at the beginning and / at the end), and instead of 80 — the port on which the connection should be made. There are several useful keys to use the utility:

    • -v — detailed output of information in the course of work.
    • -t — ensuring compatibility with the Telnet protocol.
    • -u — connection via UDP protocol. The default is TCP.
  3. Wait for the connection results:
    • If the connection is successful, the following message will appear:
      Connection to example.com 80 port [tcp/http] succeeded!

      Instead http the protocol by which the connection was made will be displayed.

    • If the connection fails, an error message will be displayed:
      connect to example.com port 80 (tcp) failed: Connection refused
      The error in the response may differ depending on the reason for the termination of the connection.

To get out of nc press combination Ctrl+C.

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