Hi Mark On 6/01/2010, at 10:04 AM, Mark Foster wrote:
If you actually search for the specific error (4.16.50) on the URL given i the bounce, the result is this:
http://help.yahoo.com/l/us/yahoo/mail/postmaster/errors/postmaster-21.html
Note it specifically uses the phrase "emails from your mail server have been generating substantial complaints from Yahoo! Mail users" - ala people are hitting the 'report as spam' buttons and some internal Yahoo magic is being applied to the IP as a result.
Thanks, I didn't read that far. It seems odd though that 4.16.55 and 4.16.56 error messages specifically mention complaints: http://help.yahoo.com/l/us/yahoo/mail/postmaster/errors/421-ts01.html http://help.yahoo.com/l/us/yahoo/mail/postmaster/errors/421-ts02.html It seems to me that the reason given in your link above of "substantial complaints" is incorrect. Maybe the Yahoo techie who wrote that got confused with the other codes.
The page further suggests the use of this form to report "if you're seeing this error consistently over an extended period of time" - http://help.yahoo.com/l/us/yahoo/mail/postmaster/defer.html .
Whenever this comes up, someone mentions Greylisting. Greylisting delays are usually in the minutes; one assumes that by the time it's posted to NZNOG, the delays have become more noticable than that.[1]
I don't think greylisting is well enough standardised to be able to say that. I've certainly seen it set at over an hour by default (though I can't remember where for now).
Given the number of times Yahoo and these sorts of errors have come up online before[2][3], i'd see it as far more of a reputation issue, to be honest. Andy D's post makes a lot of sense.
If it were reputational then SPF, reverse mapping etc would fix it, but they apparently do not. It may also be simple rate limiting, which would explain the variable lengths of delays. regards Jay -- Jay Daley Chief Executive .nz Registry Services desk: +64 4 931 6977 mobile: +64 21 678840