Can anyone please explain the difference (in layman terms) on how the FROM address is interperted by RFC 821 versus RFC 822? Why do I receive a **501 syntext error because my email gateway automated messages FROM ADDRESS **is blank but the display **FROM ADDRESS **has a [COLOR=“Blue”]valid[/COLOR] address?
Both of those RFCs are obsoleted by 2821 and 2822, so you shouldn’t be looking at them anyway.
In any case, the two RFCs are complementary, so there isn’t a difference between them.
For your specific problem, I imagine you could resolve your error by having your gateway include “donotreply@domain.com” or some other address in the from field. I don’t know what you mean about having a different from vs from display, though.