On Fri, 31 May 2002, Dave C. wrote:
> > > 2002-05-31 19:59:07 SMTP synchronization error (next input sent too soon):
> > > rejected "HELO gmx.net" H=ts46-01-qdr2264.mdfrd.or.charter.com
> > > [66.169.232.216]
> > >
> > > Wot dat?
> >
> > probably related to pipelining ? no further ideas, though.
>
> Pipelining does require sync at certin points. Proper SMTP-sender
> implementations of pipelining dont have this problem. Spamware often
> sends entire SMTP sessions in one chunk, entirely ignoring the RFC.
>
> Most likely, this was an instance of such spamware, and exim rejected
> it.
Exactly. This check was put into Exim a few releases ago. It is intended
to block messages from spammers that send out an entire SMTP session in
one packet, disconnect, and ignore any responses. In this case, Exim
noticed that there was more input after the HELO command, before it had
sent back the response. That is in violation of the SMTP protocol.
--
Philip Hazel University of Cambridge Computing Service,
ph10@??? Cambridge, England. Phone: +44 1223 334714.
