How To: Netcat – Check for open ports with the command line

Kitty Port-checking

When troubleshooting a network integration or any other connection issue in Linux, step one is usually a matter of checking to see if the network port on the other side is even responding.

Netcat -The network Swiss Army knife (Hobbit, not nmap)- is the right tool for the job.

Before we begin, NetCat needs to be installed.

# RHEL / CentOS
~$ yum install nc

# Debian / Ubuntu
~$ apt-get install nc

Once installed, you can invoke Netcat like so:
~$ nc [REMOTE_SERVER] [PORT]

Syntax:
[REMOTE_SERVER] – The server to be checked
[PORT] – The service/port to be checked

…
Connection to google.com 443 port [tcp/https] succeeded!