Re: [Exim] Escaping single dots before SMTP delivery

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Author: Andreas Metzler
Date:  
To: exim-users
Subject: Re: [Exim] Escaping single dots before SMTP delivery
On Tue, May 06, 2003 at 05:31:17PM +0100, Simon Williams wrote:
> * On Tue, May 06, 2003 at 04:58:02PM +0100, Matthew Byng-Maddick wrote:

[...]
> > If a line starts with a dot, you prepend another, what*EVER* comes after
> > it. (something which the participants in the very recent thread appeared
> > to be unaware of)


> Odd. RFC2821 specifies that message data should end with
> "<CRLF>.<CRLF>", so any line beginning with a dot and containing
> another character other than the <CRLF> pair shouldn't be treated as
> signifying the end of message data.

[...]

It is not that odd if you think about it:
* Dot-escaping is done to be able to send messages which contain a
line consisting only of single dot.
* It has to be possible to easily undo the escaping before final
delivery.

If you only replaced "." with ".." but would leave ".." unchanged
you'd end up with a line ".." in both cases and could not distinguish
whether somebody sent "." or "..".
              cu andreas