Url looks suss. Seems kinda sophisticated for the usual ups fishing scam. Here’s the text message I got leading here.
“Wishing you a bright and sunny day!” Lol, I almost want to help this guy by explaining that UPS and American companies in general have disdain for their customers and would never wish them to have anything that would not benefit the company.
I’m not up to speed on exactly how spam filters blacklist domains but I strongly suspect if Gmail thought spam was coming from email.facebook.com then it would restrict facebook.com too. That’s the only reason I can think of for creating such a clunky domain; it’s that a neater looking sub domain won’t avoid the problem - hence having to register something completely different.
That sounds like a preference that would be added by whoever configured the server rather than anything else. I’ve definitely seen situations where a third-level domain has been under the control of (or sold to) a third party and so it wouldn’t make sense to block the second-level, or other third-levels branched off from it if only one third-level misbehaved. Edit: And I don’t just mean countries that treat second-level as top-level for some uses, like, say .co.uk.
I have no idea what the defaults are for various automatic spam blockers, since both arguments have merit.