Checking if email is valid

[Chris Angelico]

On Thu, 2 Nov 2023 at 17:47, Cameron Simpson via Python-list
<python-list at python.org> wrote:
>
> On 02Nov2023 17:04, Chris Angelico <rosuav at gmail.com> wrote:
> >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.
>
> Hmm. IIRC...
>
> https://datatracker.ietf.org/doc/html/rfc2821#section-4.1.1.6
>
> I think a lot of mail receivers don't honour this one, for exactly the
> reasons above.

Yeah, and it also won't tell you if the mailbox is full, or
unattended, or if the email would be rejected or discarded for any
other reason. Which means it's not even all that useful if it IS
implemented.

ChrisA