Subject: Re: New anti spam approach
Newsgroups: gmane.mail.postfix.user
Date: 2008-05-11 11:26:49 GMT (7 years, 2 weeks, 5 days, 13 hours and 33 minutes ago)
On Sun May 11 2008 06:06:25 Jack Raats wrote: > From: "Ralf Hildebrandt" <Ralf.Hildebrandt <at> charite.de> > >> http://blog.mailchannels.com/2008/02/spammers-are-less-patient-tha > >>n.html I tried to implement this in my postfix configuration. > >> > >> Question: Is the sleep 15 command sufficient to implement this or > >> do I miss something? > > > > As far as I know this only works with smtpd_delay_reject = no > > and in smtpd_client_restrictions. The greet pause is what trips up the spambots and ratware: smtpd_delay_reject = no smtpd_client_restrictions = sleep 15, reject_unauth_pipelining This happens before the smtpd_banner is given. I don't have any data regarding effectiveness of this ploy, but I know many Sendmail postmasters are very pleased with it. > Accoording to postconf.5.html, smtpd_client_restriction, sleep is a > generic restriction, which may be used in > smtpd_recipient_restrictions. It is, indeed. But it does nothing beneficial there. > I have to study the smtpd_delay_reject = no. It means that each restriction stage is evaluated at that point in the SMTP dialogue: 1. smtpd_client_restrictions : initial connection, before banner 2. smtpd_helo_restrictions : HELO command given by client 3. smtpd_sender_restrictions : MAIL FROM command 4. smtpd_recipient_restrictions : RCPT TO command See SMTPD_ACCESS_README.html#timing for a discussion of what this entails. -- Offlist mail to this address is discarded unless "/dev/rob0" or "not-spam" is in Subject: header