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Re: Yahoo Mail Filtering

2010-07-31 18:27:27

Very odd. I don't see how yahoo's "shred" logic or deferrals promoting 10+ retries before it finally accepts, and they all seem to finally make it, helps anyone.

Thanks for the link.


Hector Santos

Laura Atkins wrote:

On Jul 31, 2010, at 11:22 AM, Hector Santos wrote:

J.D. Falk wrote:

It's not the wikipedia definition of greylisting, but they do use 4xx replies 
to control the flow of inbound mail.
Ok, now I am starting to see 45x "grey listings", here is snap shot of a mail 


There are multiple retries spread across different machines.

Do you think they need the same exact IP or they support a class C
machine distribution?

Yahoo isn't greylisting.

"Yahoo is not keeping track of the mail it rejects and is not reliably allowing 
email through on the second attempt. There are a couple reasons why Yahoo is 
deferring mail.

        • Shedding load in a generic and non-specific way.
        • Shedding load by temporarily refusing mail from specific IPs.
In the first case, the shedding of load means nothing more than Yahoo is shedding 
load. There is not really anything the sender can do to compensate for this, nor is 
there any thing the sender is doing (except possibly send mail to Yahoo at the same 
time as the rest of the world) to precipitate the blocking."


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