Why is Sendmail still around?

[RW]

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,

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.  

There are some services, like Fastmail/Pobox, that don't block senders
just because they are sending directly from a dynamic pool, but they
aren't really doing anyone any favours because they still apply
Spamhaus XBL.


> even though their own ranges are full of compromized
> "Windows" PCs that spam the world.

This is less important than it used to be. These days spammers put a
lot of effort into compromising vulnerable servers, sometimes this
allows their spam to pass SPF, DKIM and even DMARC.

In some cases a home server with an MTA configured to use a  smarthost
can be a gift to a spammer if it's compromised.