All the talk about overhead, spammers not honoring 5xx responses seems, to me, to miss a major point. We all accept that your gonna get a few false positives (particularly with tactics like blocking /8 address ranges), now what would you rather the sender of those genuine emails gets?
1) A failure with a valid reason and maybe contact address. or 2) Nothing until the previous mailer to yours in the chain gives up retrying, probably best part of a week later, and times the messages out (possibly with a message implying that you have a rubbish mail service that doesn't respond to connection attempts). Chris > -----Original Message----- > From: Simon Byrnand [mailto:[EMAIL PROTECTED] > Sent: 28 July 2003 01:26 > To: Matt Kettler; Turgut Kalfaoglu > Cc: [EMAIL PROTECTED] > Subject: Re: [SAtalk] Block an entire Network? > > > At 23:17 25/07/2003 -0400, Matt Kettler wrote: > >At 03:09 PM 7/25/03 +0300, Turgut Kalfaoglu wrote: > >> > >How does one go about blacklisting an entire network, > say for example > >> > >[EMAIL PROTECTED] does not seem to work? > >> > >>If you have the option; block it from the firewall OR router. > >>It saves SO much overhead! > > > >Actualy, it is the lowest overhead to 5xx it at the MTA > level.. if you > >block it at the firewall or router, it will keep trying > repeatedly to > >connect to deliver the mail.. > > That unfortunately assumes that the software that spammers > use to send spam > actually listens to 5xx MTA rejections - in fact 90% of them > don't, they > just drop the connection and try again and again despite the 5xx > rejections...(thats one almost sure fire way of picking out a > spammer from > someone genuine - any genuine sending MTA won't try > repeatedly to send the > same messages after 5xx rejects) > Chris -- ---- Chris Seelig Phone: +44 1235 446234 Network Development Group, Fax : +44 1235 445727 Information Technology Department Email: [EMAIL PROTECTED] Rutherford Appleton Laboratory, WWW : http://www.itd.clrc.ac.uk/ Chilton, Didcot, Oxfordshire, OX11 0QX, United Kingdom. ------------------------------------------------------- This SF.Net email sponsored by: Free pre-built ASP.NET sites including Data Reports, E-commerce, Portals, and Forums are available now. Download today and enter to win an XBOX or Visual Studio .NET. http://aspnet.click-url.com/go/psa00100003ave/direct;at.aspnet_072303_01/01 _______________________________________________ Spamassassin-talk mailing list [EMAIL PROTECTED] https://lists.sourceforge.net/lists/listinfo/spamassassin-talk
