SPAM This thread is for random spam!!

[Zarjazz]

I'm just curious how one does that? I regularly get mails "from" people I used to know who aren't in my address book but a cursory click exposes them as juntyedmcwankstain@somemadeupurl.com or somesuch, but this one doesn't.

Fundamentally the SMTP protocol has no such restrictions, any piece of mail software can set whatever headers it wants. That's why extra technologies why SPF and DKIM were create to add verification . Along with content checks, spam detection is then a game of using all that information to decide if that person / ip address is allowed to send emails for the domain they claim to be part of. The reason you see so few emails in the format you asked about is that they are more likely to be classed as spam (it's harder to pretend to be a legit domain).