> You had me at EHL0.
You just reminded me of my time working at Sendmail, where I often had to telnet to port 25 of some machine, and pretend to be a mail server sending email.
I used to be able to send all the commands without having to look them up. Not sure I could still do that today.
I think can still do it, 30 years after I last had to. The trauma of debugging sendmail m4 config issues for hours while the company e-mail remained dysfunctional has permanently etched it into my mind.
Wietse Venema saved us all.