Check if a port on a remote system is reachable (without telnet)


I wanted to check if our customer had an issue with network access. I asked him to run telnet command, but because of their security reasons, telnet rpm was not installed at all.


One of the solution would be to run nc 🙂 but of course nc was not installed. 🙂

The following command helped me in that situation:

cat < /dev/tcp/

The port is open if there is no output, but if you receive the following, then the port is closed:

-bash: connect: Connection refused
-bash: /dev/tcp/ Connection refused