Why is Sendmail still around?

@lbutlr kremels at kreme.com
Sat Mar 30 15:15:00 UTC 2019

On 30 Mar 2019, at 08:54, RW via freebsd-questions <freebsd-questions at freebsd.org> wrote:
> On Sat, 30 Mar 2019 03:41:14 +0100 Polytropon wrote:
>> On Fri, 29 Mar 2019 14:01:10 +0000, Steve O'Hara-Smith wrote:
>>> 	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.  
>> 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 
> 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.

Im finding's you'r mis'use of apostrophe's disturbing.

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