how to test ports – Telnet, Expect, Bash, Netcat, Nmap

• https://www.redhat.com/sysadmin/stop-using-telnet-test-port
• https://news.ycombinator.com/item?id=35621441

For “security reasons” telnet and nmap are not included in the basic set of utilities present on a production server. And why would you install software, that you usually don’t need there? But occasionally these tools are needed and should be available for installation. I certainly like telnet and nmap for the described purposes.