Competent public ESPs like gmail and aol have implemented email authentication for ages. (They still have the whack a mole problem of throw away accounts - but there is no forgery.) The only unauthenticated email is from incompetent (wrt email) ISPs (I'm resisting the temptation to name names - you probably don't know who you are) and small operators who don't want to use a commercial service, but don't actually know what they are doing (and get mad if you try to educate them).
So just stop tolerating unauthenticated email. I will admit that gmail, for instance, does not provide a button for end users to "stop tolerating unauthenticated email". However, they incorporate that as part of their mysterious and hidden process of spam control.
Authored Comments
Competent public ESPs like gmail and aol have implemented email authentication for ages. (They still have the whack a mole problem of throw away accounts - but there is no forgery.) The only unauthenticated email is from incompetent (wrt email) ISPs (I'm resisting the temptation to name names - you probably don't know who you are) and small operators who don't want to use a commercial service, but don't actually know what they are doing (and get mad if you try to educate them).
So just stop tolerating unauthenticated email. I will admit that gmail, for instance, does not provide a button for end users to "stop tolerating unauthenticated email". However, they incorporate that as part of their mysterious and hidden process of spam control.
I was first introduced to Saint Columba in a novel by Nancy Farmer - the Heroes take refuge in Columba's exilic retreat.
http://www.amazon.com/Islands-Blessed-Richard-Atheneum-Hardcover/dp/1416907378/