Date: Sat, 30 Mar 2019 09:14:57 -0600 From: "@lbutlr" <kremels@kreme.com> To: "James B. Byrne via freebsd-questions" <freebsd-questions@freebsd.org> Subject: Re: Why is Sendmail still around? Message-ID: <6F74B111-CE53-4122-ACBE-1AB0311FE224@kreme.com> In-Reply-To: <20190330145410.17cfd72d@gumby.homeunix.com> References: <4101a1092141b58e05ef7552278b15ff@kathe.in> <b6024975-31b1-e08b-46ee-e18597ada469@netfence.it> <b13d35f7472591ebd90c02d100b9ce80@kathe.in> <20190329121212.1f12fed7.freebsd@edvax.de> <20190329140110.3c7102ef876f3a1e58ea467b@sohara.org> <20190330034114.54ae2511.freebsd@edvax.de> <20190330145410.17cfd72d@gumby.homeunix.com>
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On 30 Mar 2019, at 08:54, RW via freebsd-questions = <freebsd-questions@freebsd.org> wrote: > On Sat, 30 Mar 2019 03:41:14 +0100 Polytropon wrote: >=20 >> On Fri, 29 Mar 2019 14:01:10 +0000, Steve O'Hara-Smith wrote: >=20 >>> I wouldn't attempt to run an outgoing mail server doing >>> direct MX lookup and delivery these days they anti-spam measures >>> are a nightmare. OTOH reliable delivery relays are not that common >>> either. =20 >>=20 >> Yes, it's not as easy anymore... You have to fight "we know better >> than you!" providers who consider every IP from a dynamic range >> a spammer, That is a fight you cannot ever win. > They pretty much have to. Most spam is caught by simple DNS based > tests which rely on assuming that no dynamic IP addresses sends direct > to MX. In particular most blocklists can't distinguish between a spam > source and a dynamic address, because an infected machine can cause=20 > hundreds of dynamic addresses to be listed. I consider every mail from a dynamic IP address to be a spammer. There = is *NO* reason for someone on a dynamic IP to be sending mail directly = to my mailserver, they need to use their provider's mailserver or some = mailserver that trusts them. I've been running a mail server since 1993, and one of the first things = I did when spam really started to become a problem was to try to block = dynamic pools (this was long before RBLs). In fact, the primary reason that I switched to postfix was for better = tools to match helo and rDNS names for the purpose of blocking spam = (which was nearly all from dynamic pools in the early days of spam). I still have 1500+ lines of checks, probably unneeded now, that look for = common dynamic pool tokens and reject them. --=20 Im finding's you'r mis'use of apostrophe's disturbing.
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