Checking if email is valid

[Alan Bawden]

Chris Angelico <rosuav at gmail.com> writes:

   On Thu, 2 Nov 2023 at 15:20, AVI GROSS via Python-list
   <python-list at python.org> wrote:

   > Yes, it would be nice if there was a syntax for sending a test
   > message sort of like an ACK that is not delivered to the recipient
   > but merely results in some status being sent back such as
   > DELIVERABLE or NO SUCH USER or even MAILBOX FULL.

   Yes, it would! Spammers would be able to use this syntax to figure out
   exactly which addresses actually have real people connected to it. It
   would save them so much trouble! Brilliant idea.

That sounds like the SMTP "VRFY" command.  And spammers _did_ abuse it
in exactly this manner.  And so pretty much every mail server in the
world disabled VRFY sometime in the 90s.

- Alan