So they use a registered ip proxy to your own email server. I've been doing that for a super long time, and it's a great solution, at least until about 5 years

So they use a registered ip proxy to your own email server. I've been doing that for a super long time, and it's a great solution, at least until about 5 years ago. Most providers will blacklist anyone who isn't one of them. So I front my home email server with a big account to relay in and out of. It kinda sucks, but all my stuff just works. So I can happily fire up my Macintosh II, load up Outlook 98 and read email. I use Office 365 to front my domain, I think it's like $12 a month for the corporate version so I can have it front domain emails. And that means I get office for all my devices so I'm not the one having to deal with having old versions of stuff.