This article will show you how to Telnet via BASH script and return the status as open or close. This has been tested on CentOS/RedHat and hopefully should work on all other Linux distributions as well.
Create a file telnet_script.sh. This script is to Telnet SSH port i.e. 22
# vi telnet_script.sh
#!/bin/bash echo "172.16.66.200 22" | \ while read host port; do r=$(bash -c 'exec 3<> /dev/tcp/'$host'/'$port';echo $?' 2>/dev/null) if [ "$r" = "0" ]; then echo $host $port is open else echo $host $port is closed fi done
This is when Telnet for SSH Port responds OK.
This is when Telnet for SSH Port responds FAIL.
If you encounter any errors during the process, let us know via Contact Us and will try our best to help.