[dba-Tech] Gmail Identification

Now and then I see a message in a Gmail thread (most recently in the
AccessD thread) that says "This mail may not have been sent by <some
name>." It's no big deal, but I'm curious as to how Gmail determines the
authenticity of a sender. Anyone know?

-- 
Arthur
Cell: 647.710.1314

Thirty spokes converge on a hub
but it's the emptiness
that makes a wheel work
   -- from the Daodejing