From: "Eric Thomas"

> ........   Outlook sent '.shape' but
> did not double the period! As this style snippet happens to be
> unimportant, messages display normally if the MTA accepts '.shape'
> as 'shape' with no further ado. SMTPL did not do that, as I like for
> errors to be visible so that they can be corrected, but as it is
> Microsoft I have no choice but to accept that I am wrong and they
< are right, so I have changed SMTPL to accept this sequence.

The SMTP Transparency provision (RFC 2821, subclause 4.5.2) requires:

 -  Before sending a line of mail text, the SMTP client checks the
      first character of the line.  If it is a period, one additional
      period is inserted at the beginning of the line.

   -  When a line of mail text is received by the SMTP server, it checks
      the line.  If the line is composed of a single period, it is
      treated as the end of mail indicator.  If the first character is a
      period and there are other characters on the line, the first
      character is deleted.

If I understand the explanation here, Microsoft is clearly wrong--it didn't
double the period, as required--but SMTPL did something more extreme than
simply losing the period, which would also be wrong.

It's not an SMTP end-of-message flag unless the ENTIRE LINE consists of a
single period.

Hal Keen