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Subject: Re: undisclosed_recipients_header
From: Wietse Venema (wietseporcupine.org)
Date: Thu Sep 14 2000 - 08:20:22 CDT

Damian Gerow:
> I've been playing around with Postfix-19991231-pl08, and I've noticed
> something funky.
>
> When sendmail mail manually (i.e. telnetting to port 25, etc.), and not
> specifying a "To: " field in data, postfix sets the "To:" field to an
> "undisclosed_recipients_header". I can't find any documentation on
> this. I can set it to other values no problem, I'm just wondering if
> it's possible to use the "rcpt to:" client submission if the recipients
> header actually isn't specified.

RFC 822 (which was written almost 10 years ago) requires the presence
of at least one destination message header.

Thus if neither a To: or Cc: is present, Postfix adds one as required
by the RFC.

Using RCPT TO addresses is a bad idea, because it would reveal Bcc:
recipients.

        Wietse