Last Updated: 2024-11-23

• it is used for connecting to TCP ports (UDP ports need nc - netcat). FYI: HTTP rides atop of TCP, which rides atop of IP
• e.g. if I was getting timeouts talking to SendGrid from a server, I might (also from the same server) try: $ telnet smtp.sendgrid.net 587 and directly test the connectivity
• in order to exit from telnet, the standard command won't work (presumably because you might want to send these characters to the remote port on the other machine). Therefore, to exit, you need to first press Cntl-] and then type quit