Go Systems Programming

About the netcat utility

There are times that you will need to test a TCP/IP client or a TCP/IP server: the netcat(1) utility can help you with that by playing the role of the client or server in a TCP or UDP application.

You can use netcat(1) as a client for a TCP service that runs on a machine with the 192.168.1.123 IP address and listens to port number 1234, as follows:

$ netcat 192.168.1.123 1234

Similarly, you can use netcat(1) as a client for a UDP service that runs on a Unix machine named amachine.com and listens to port number 2345, as shown here:

$ netcat -vv -u amachine.com 2345

The -l option tells netcat(1) to listen for incoming connections, which makes netcat(1) to act as a TCP or UDP server. If you try to use netcat(1) as a ...