On Wed, 7 Apr 1999 08:21:35 -0400 (EDT), [EMAIL PROTECTED]
wrote:
>About the sender address used by qmail, I understand that it's difficult to
>choose an address given that the RFC's don't reserve any for this purpose.
>However the choice of an "ilegal" address seems to me a little unfortunate, even
>more since it's hard coded. Though it could be useful in most cases, some RFC
>compliant product, as Microsoft Exchange in this case, would be affected. Many
>founded critics to Microsoft products are based on their standards violations.
>It's surprising that an excelent program as qmail suffers a "similar" flaw.
One could argue that the "From:" address at the SMTP level since it is
trivial to fake serves only one purpose: to direct bounce info. Thus,
there is no reason to check this address, unless one needs to bounce
the message. Of course, the syntax has to be good enough for the SMTP
dialog. The problem, IMHO is that the use of this address has been
extended as a SPAM filter to force spammers to use valid envelope
senders (valid=correct syntax and existing domain).
This adaptation is trivial for spammers, but the filter has negative
consequences for normal mail. The rfc talks about how a message should
be composed, not received. rfc compliance for recipients means only
that they should accept correctly formatted messages. It does not say
that any non-conforming message should be rejected. This is a BIG
difference.
qmail as an example accepts as much as possible, except the bare-LF
which is rejects because doing anything else risks message corruption.
The SENDER syntax restriction has no such redeeming features.
-Sincerely, Fred
(Frederik Lindberg, Infectious Diseases, WashU, St. Louis, MO, USA)
