I'm at least an instance of one that demonstrates that it's possible. The person you link to sounds misconfigured to some degree, but in the main two things the

I'm at least an instance of one that demonstrates that it's possible. The person you link to sounds misconfigured to some degree, but in the main two things they don't mention are whether they are using static IPs (as I am), or if they tried emailing postmaster@ to try and smooth out their difficulties. There is still a collegial network of people who run this stuff all over the world, and I'm certainly not the only person running a closet mailserver.