> > - 3. The sending IP is using a broken mailer that's
> > generating bare LFs, and this mailer regards the
> > resulting temporary error code generated by qmail
> > as 'Please try again straightaway'.
> >
> > I'd be particularly interested to know if anyone has come
> > across the 3rd possibility...
>
> Yup, I see it happen on occasion. I usually sniff the message
> off the wire
> to see if its anything I care about then toss a deny rule into
> my tcprules
> for that ip to stop the hammering. Sending the remote party a
> message is
> nice too though I rarely get any cluefull responses.
>
I recently had this problem - some mailserver (Something Microsoft-based)
kept trying to get a bare LF message to me over and over again, and
sending the remote party a message about it did not yield anything like a
clueful response.
However, in this experience I realized I don't understand a couple of
things about the whole bare LF issue - according to the page Dan Bernstein
set up, bare LFs are prohibited by 822bis, but as far as I know, 822bis is
still in drafting stages ( not a standard yet ), so that's not exactly
something I can tell the remote party in trying to convince them to fix
their mailer.
qmail-smtpd does not convert bare linefeeds because it doesn't want to
corrupt data - instead if an e-mail it receives has bare linefeeds, it
just rejects the message. Sendmail just goes ahead and converts the bare
linefeeds to CRLF, and accepts the message. The question I have is, and
excuse my ignorance if it's something silly: why not just accept the bare
linefeeds? From what I can understand in RFC822, there's nothing wrong
with bare linefeeds in the body of the messages as long as the headers
have all the right CRLFs. From looking through qmail archives and reading
a few webpages, all I can find is some reference to the fact that you
shouldn't have bare linefeeds after the smtpd process. Anyone have any
more specifics about this? Is it to protect mailers that don't know how
to interpret bare linefeeds? Or something integral to the MTA?
Sorry if this is something obvious, or if there is some piece of
documentation out there I'm missing; if there is, please point me in the
right direction.
Thank you for your time,
Jamie Blondin
