On Thu, Aug 23, 2001 at 01:28:25PM +0100, Richard Underwood wrote:
> Kolus Maximiliano wrote:
> >
> > Instead of sending a FIN, the connection closed using RST (i
> > believe it's because the originating process died), for some reason
> > exchange couldnt see it and continued to send packets until his buffer
> > was emptied, then he ignored the 451 and showed the 499 (aka
> > connection reset by peer). Before getting flamed, i know that it's
> > exchange's fault to ignore the 451, but, shouldnt the connection be
> > closed by FIN instead of RST?
>
> I get this a lot with the microsoft SMTP service (comes with IIS)
> talking to qmail. If a website is using CDONTS, it's a particular
> problem - if a connection is dropped, the SMTP service will re-try
> without any delay and won't back off.
http://www.space.net/abuse/rbl/stray.html (great page, Maex :)
[snip]
> A "fix" which I have been considering is, instead of sending a
> 451 followed by a reset, is to sleep for 5 seconds, send the 451,
> sleep for another 5 seconds and then reset the connection.
I have been considering almost the exact same fix.
> At the very worst, this will reduce the connections to one per 5
> seconds. At the best, it'll look like a valid SMTP conversation to the
> remote MTA and might actually give it a chance to parse the response
> and include the message in the bounce - instead of the usual "reset by
> peer" junk.
It's a 4xx so the user won't get the bounce for a long time anyway.
Greetz, Peter
--
Against Free Sex! http://www.dataloss.nl/Megahard_en.html
