Maintaining a whitelist

Vernon Schryver
Fri Jul 20 15:14:05 UTC 2001

> From: Gustav Foseid <>

> ...
> > Perhaps I need to change how dccm treates mail addressed simultaneously
> > to white-listed and unlisted addressees.  Currently, the message
> > is rejected, discarded, or delivered to all addressees.  I've resisted
> > doing this, because it requires that dccm record the addressees at
> > the start of the SMTP transaction and at the end remove those who should
> > not receive the message.  It is also not clear what SMTP reply status
> > I should generate for a message that is partly delivered.
> > What do you think?
> I don't know very much about milter, but there is only one way to handle
> this, taht I can see. The message must be accepted with "250 OK" and a
> bounce message must be sent reporting a delivery failure to each of the
> recipients that did not receive the e-mail.

Bounce messages for DCC rejections are sent by the remote SMTP client,
not the system using the DCC.

Why would those recipients who didn't get the message because they
consider it spam by virtue of not being in the white list want a
delivery failure message?

It is possible to reject individual SMTP envelope Rcpt_To values, but
the DCC cannot know it should tell sendmail to reject the message
until after the body has been received as part of the DATA command.
Sendmail can only say to the SMTP client "yes, your DATA command was
ok" or "no, it was bogus."  That single result code applies to the
entire SMTP transaction and all recipients corresponding to Rcpt_to
commands not previously rejected (in this case all of them).

After thinking about it for a day, my inclination is to say that
when there is a mixture of white-listed and not white-listed envelope
To values, the message should be treated as "DISCARD" for the not
white-listed values.

Vernon Schryver

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