Re: Yahoo Mail Filtering

J.D. Falk wrote:

> On Jul 20, 2010, at 7:46 PM, Hector Santos wrote:
> 
> It's not the wikipedia definition of greylisting, but they do use 4xx replies to control the flow of
inbound mail.

A SMTP customer I was working, provider a link showing a greylist 
transaction. From my perspective, the user spoke as it was a 
persistent  behavior.

But I have yet to see it in the 2-3 weeks of exploring this YAHOO 
issue with the customer.  So it made me think the user was 
experiencing maybe a YAHOO exploration into greylisting at the time or 
it was done on a per IP basis or something. I have not seen it in all 
our send mail attempts.

>> Absolutely, no pattern, inconsistent "DISCARDING" and delivery of mail.
> 
> Often, filters will be reacting to a system-wide pattern that 

 > an individual user can't see.  To give an overly
 > simplified and surely incorrect example, if a spammer were sending
 > "test #4" all day, then your entirely legitimate "test #4" would
 > get caught too.

> 
> That said, if the mail is being discarded due to system-wide