Spam from the same domain
in [Postfix]
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From: listadecorreo on 26 Mar 2010 16:54 Hello in the last month I revived a lot of spam from user_non_exist(a)mydomain to user_exist(a)mydomain..... can I block all received externals mails from my domain to my domain... I use postfix with amavis (spamassassin/clamav) thanks in advance
From: Mark Goodge on 26 Mar 2010 17:14 On 26/03/2010 20:54, listadecorreo wrote: > > Hello > > in the last month I revived a lot of spam from user_non_exist(a)mydomain > to user_exist(a)mydomain..... can I block all received externals mails > from my domain to my domain... It's very easy to block mails from fake_user(a)domain to real_user(a)domain. Just turn on sender address verification for your own domains. See http://www.postfix.org/ADDRESS_VERIFICATION_README.html for details on how it's configured. Blocking forged mails from real_user(a)domain to real_user(a)domain is harder, as if any of your users use SMTP servers other than your own then it's very hard to distinguish between that and forgeries. Mark
From: Daniel L'Hommedieu on 26 Mar 2010 17:21 On Mar 26, 2010, at 17:14, Mark Goodge wrote: > On 26/03/2010 20:54, listadecorreo wrote: >> >> Hello >> >> in the last month I revived a lot of spam from user_non_exist(a)mydomain >> to user_exist(a)mydomain..... can I block all received externals mails >> from my domain to my domain... > > It's very easy to block mails from fake_user(a)domain to real_user(a)domain. Just turn on sender address verification for your own domains. See http://www.postfix.org/ADDRESS_VERIFICATION_README.html for details on how it's configured. > > Blocking forged mails from real_user(a)domain to real_user(a)domain is harder, as if any of your users use SMTP servers other than your own then it's very hard to distinguish between that and forgeries. Mark, I find that using the Zen spamhaus list does a very good job at blocking mail from real_user(a)example.com, for my domains example.com. Daniel
From: "Steve" on 26 Mar 2010 17:51 -------- Original-Nachricht -------- > Datum: Fri, 26 Mar 2010 21:54:43 +0100 > Von: listadecorreo <listadecorreo(a)sbd.cadinor.com> > An: postfix-users(a)postfix.org > Betreff: Spam from the same domain > > Hello > > in the last month I revived a lot of spam from user_non_exist(a)mydomain > to user_exist(a)mydomain..... can I block all received externals mails > from my domain to my domain... > Are your users sending mail over your infrastructure? Do you force them to use SMTP AUTH/SASL? If so then you might have a look at reject_sender_login_mismatch to stop forgeries from your own domain. > I use postfix with amavis (spamassassin/clamav) > > thanks in advance -- Sicherer, schneller und einfacher. Die aktuellen Internet-Browser - jetzt kostenlos herunterladen! http://portal.gmx.net/de/go/atbrowser
From: Ansgar Wiechers on 26 Mar 2010 19:13 On 2010-03-26 Steve wrote: > Von: listadecorreo <listadecorreo(a)sbd.cadinor.com> >> in the last month I revived a lot of spam from >> user_non_exist(a)mydomain to user_exist(a)mydomain..... can I block all >> received externals mails from my domain to my domain... ^^^^^^^^^^^^^^^ > Are your users sending mail over your infrastructure? Do you force > them to use SMTP AUTH/SASL? If so then you might have a look at > reject_sender_login_mismatch to stop forgeries from your own domain. The OP wants to block external, not internal senders. Regards Ansgar Wiechers -- "Abstractions save us time working, but they don't save us time learning." --Joel Spolsky
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