Scan open port using netcat on Ubuntu

By default ubuntu comes with pre-installed tool called netcat (nc), using netcat we can scan for open port on other computer that connected to the same network.

Because netcat comes pre-installed on ubuntu, so we don't need to install it, we can just use it right away, the command name is 'nc'.

So let's just scan our own computer for port 22 which is port for ssh server, here's the command:

nc -zv [ip-address] [port-number]

Example:

nc -zv 127.0.0.1 22

nc -zv localhost 22

It is also possible to scan range of port number, like this:

nc -zv localhost 22-80

This will scan from port 22 to 80 and will display the result.