Comment by jedberg

9 days ago

> 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.

4 comments

jedberg

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frumplestlatz  9 days ago

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.

  EHLO example.com
  MAIL FROM:<foo@example.com>
  RCPT TO:<bar@example.com>
  DATA
  Subject: Hello, World

  I have crawled through the depths of hell to deliver unto you this message.
  .

Wietse Venema saved us all.

  • eqvinox  9 days ago

    I haven't worked at sendmail or even anything e-mail related, and I can do that… just enough e-mail fixing as side work. Let's call it sysadmin calluses.

    What made me stumble recently was having to talk LMTP to fix a mailman setup. Cheeky fuckers changed EHLO into LHLO for LMTP. (To avoid any mixups between the protocols, which is fair.)

  • Izkata  9 days ago

    From and To should be repeated below DATA, those are the actual email headers. And From at least doesn't need to match MAIL FROM.

    • nedt  8 days ago

      Also TO doesn't need to match. When you send to a group of BCC the envelope To has to specify the exact recipient, but the DATA doesn't. Similar with the envelope From and the one in the DATA - also useful to control bounces or who gets a reply.

      Yeah I know the protocol and can do that manual, because I had to debug it often enough.