email and smtplib modules

[mark.greenbank]

Hi,

I'm writing a small script that generates email and I've noticed that:

1) one should add the 'To' and 'CC' headers to the email message
2) one needs to specify the recipients in the smtplib sendmail() method

Can someone explain how these are related?

Thanks,
Mark

[Mike Meyer]

"ma************ @gmail.com" <ma************ @gmail.com> writes:

Hi,

I'm writing a small script that generates email and I've noticed that:

1) one should add the 'To' and 'CC' headers to the email message
2) one needs to specify the recipients in the smtplib sendmail() method

Can someone explain how these are related?

Sure.

It's all to do with smtp. With smtp mail, as with paper mail, there is
an "envelope" that has addresses on it that the mail system uses to
deliver messages, and the "letter", that has addresses in it that are
displayed to the end user.

The To: and Cc: headers in the message itself are in the letter. The
end user sees those. smtp servers ignore them.

The recipients passed to the smtplib sendmail() method go on the
envelope. The smtp server will deliver to those addresses, and they
won't be shown to end users.

This design makes many things possible. Most used these days is spam
delivered to one address while apparently to another.

<mike
--
Mike Meyer <mw*@mired.or g> http://www.mired.org/home/mwm/
Independent WWW/Perforce/FreeBSD/Unix consultant, email for more information.

[Roman Neuhauser]

# mw*@mired.org / 2005-04-09 16:42:04 -0500:

"ma************ @gmail.com" <ma************ @gmail.com> writes:

Hi,

I'm writing a small script that generates email and I've noticed that:

1) one should add the 'To' and 'CC' headers to the email message
2) one needs to specify the recipients in the smtplib sendmail() method

Can someone explain how these are related?

...
This design makes many things possible. Most used these days is spam
delivered to one address while apparently to another.

What about mailing lists? Quoting from your message as it arrived
here:

Return-Path: py************* *************** *************** *************** ***@python.org
X-Original-To: ne************* *************** **@sigpipe.cz
From: Mike Meyer <mw*@mired.or g>
To: py*********@pyt hon.org

For the OP:

Return-Path: header contains the envelope sender (SMTP MAIL command)
X-Original-To: is the envelope recipient (SMTP RCPT command)

So, despite the email claiming to be sent from Mike to the list,
it's actually from the list to me.

Please take Mike's note about spam with two grains of salt, the
distinction between headers and envelope is vital to the SMTP
protocol and many services built around it.

--
How many Vietnam vets does it take to screw in a light bulb?
You don't know, man. You don't KNOW.
Cause you weren't THERE. http://bash.org/?255991

[mark.greenbank]

Hi Mike,

Thanks for the quick tutorial :) Quite helpful.