Importing Mails without "to" header

[Phil Chambers]

On Fri, 15 Feb 2008 14:31:27 -0500 Larry Rosenbaum <rosenbaumlm at ornl.gov> wrote:

> > > This is valid:         To: undisclosed recipients :;
> > > This is not:           To: <undisclosed recipients>
> > >
> > 
> > I would say that the former is not actually valid, though the syntax looks
> > correct. RFC2822 section 3.6.3 says that To:, Cc: and Bcc: must contain at
> > least one address.
> 
> Not exactly.  Bcc: can be empty (note that the syntax line in 3.6.3 is
> slightly different; it allows either address-list or CFWS).  Also, To: and
> Cc: must contain an "address-list", but this requirement can be satisfied by
> an empty group construct, as in the first example above. (In a group
> construct, the "mailbox-list" is optional.)
> 
> >  None of the three is
> > required, so if there is to be no recipient address in the header, the
> > To: and
> > Cc: lines should be absent.  (If I remember correctly, RFC822 did
> > require
> > either To: or Cc: to be present.)
> 
> It requires either To:, Cc:, or Bcc: to be present.  If there is no
> recipient in the header, the message can have either an empty Bcc: or a To:
> with an empty group construct.  I don't think this changed with RFC2822, but
> I can't find anything in the document that indicates that a destination
> field is required.

I do not dispute that an empty group is syntactically correct, but section 
3.6.3 actually says "one or more addresses (either mailbox or group syntax). 
Note the first part: "one or more addresses".  An empty group does not satisfy 
this requirement because it contains no address.

RFC822 made it explicit in section 4.1 that there had to be at least one 
"destination" field in the message. (Destination fields are To:, Cc:, Bcc: and 
their 'Resent-' versions.)  That is not in RFC2822.

Phil.
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Phil Chambers (postmaster at exeter.ac.uk)
University of Exeter