It takes a long time to build up IP reputation if you run your own infrastructure. Even today after a year+ on the same IP, DKIM/SPF/DMARC, senderscore of 100 and transactional email only, Yahoo still randomly blacklists us for weeks at a time. Good luck getting in touch with a human to figure out why when you aren't Gmail or another big player in the industry.

Aside from Yahoo though, we generally haven't experienced any blacklisting or deliverability issues. It does require time to setup properly and maintain however, you can't just set it up and forget about it.

That's exactly part of the problem. If email went back to decentralization properly, the whole idea of ip reputation could go away, which is genuinely wrong and against email in the first place.

As someone who's had his entirely legitimate, wholly none-spamming email accounts blacklisted (numerous times) because he used the same shared server as someone less than saintly, I can attest that this is actually a genuine and existant concern.

Sure, it's 'easy' to get around, by throwing more money and complexity at the problem, but it isn't some made up tale.

I would not use a shared server for E-mail hosting, for this exact reason. Even if you are the only person on the IP, you need to watch out your first couple of months because the IP you have could have been misused in the past. If you find your new host’s IP on a blacklist, request a new IP from your provider.

>Can you get on a blacklist erroneously? Yes.

Can any random adversary easily have you blacklisted just for fun?

Can some Wordpress or other such service you run with your own email get you in trouble?

What about any when viruses (and botnets) in any PCs you have in your company go bezerk with your account?

And so on...