Yahoo and their mail filters..

Erik (Caneris) erik_list at
Wed Feb 25 03:11:24 UTC 2009

Ditto. They appear to use some strange form of greylisting combined with blocking. What seems to help is SPF and PTRs that match the EHLO your MTAs will send. We didn't implement Domain Keys / DKIM. 

On a related note, don't get me started on Hotmail. They used to (still do?) silently swallow mail into a black hole after accepting it. No NDR, no spam folder, just good ol' mail shredding without anyone knowing. Again, SPF and PTRs seem to help. 

Oh yeah, make sure you're not sending spam to them. That might help too. ;)

From: Joe Abley [jabley at]
Sent: Tuesday, February 24, 2009 9:41 PM
To: Micheal Patterson
Cc: nanog at
Subject: Re: Yahoo and their mail filters..

On 24 Feb 2009, at 21:27, Micheal Patterson wrote:

> This may be old news, but I've not been in the list for quite some
> time. At any rate, is anyone else having issues with Yahoo
> blocking / deferring legitimate emails?

Yes. Everybody else.


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