[Dovecot] Sending email using IMAP

Marc Perkel marc at perkel.com
Sat Nov 4 14:53:29 UTC 2006

Magnus Holmgren wrote:
> On Friday 03 November 2006 19:36, Marc Perkel took the opportunity to say:
>> IMAP requires a password. SMTP it's optional. I think that consumer SMTP
>> should be replaced with not only something that requires a password, but
>> that the user has to log into the account that they are sending email
>> from. SMTP doesn't have to be tied to IMAP accounts. If you have an SMTP
>> account you can spoof anyone. My idea with IMAP sending is to deny the
>> ability of the sender to use a different email address that the one that
>> they are logged into. This is to prevent spam and spoofing.
> You never give up, do you? Every time you propose submission by IMAP many 
> people tell you that there is no fundamental difference between that and 
> authenticated SMTP. Every ISP in the world, including the large-scale 
> spammers who act as ISPs themselves, would have to employ suitable policies 
> to avoid transmitting spoofed email. SMTP will still be used to transmit the 
> mail to its destinations. Real authenticity is achieved using digital 
> signatures, e.g. DKIM, in combination with SPF and your personal trust 
> preferences. For example, GMail allows their users to send mail from any 
> email address they can demonstrate that they own. That's good, that's what 
> yoy want, and it is completely unrelated to IMAP.

There is a fundamental difference.

1) You can use SMTP or authenticated SMTP to authenticate and send email 
through ANY server and it doesn't require that the authentication have 
anything to do with the authentication of the IMAP account. If you had 
an IMAP protocol to send email then you could lock out the SMTP 
protocols for end users and force the to have to authenticate using the 
same protocols. This gives you several advantages. You can make it so 
that the from address and reply to address match the IMAP account 
prohibiting spoofing of email addresses. It can be used to prevent user 

2) It eliminated 50% of user setup in that once you set up IMAP you need 
not set up oupgoing email.

3) It gets you around port blocking. If you can receive email you can 
send email This is good for those traveling who have trouble finding a 
working SMTP server.

4) A server who advertizes through DNS that they have these restrictions 
can prevent spam as other servers can reject spam from that domain that 
comes from outside the rules advertized.

5) Why use 2 protocols when you can use one?

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