Hi Jay, On 6/Jan/2010, at 10:17 , Jay Daley wrote:
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.
I've had this happen on a recently (last 6 months) mail server, that was sending out less than 30 emails per day. I suspect that the reason the server was flagged (with the same error) is that the IP range may have previously being in a "dial-up" and/or DSL range.
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).
I'm not knowledgeable enough to know for sure about Yahoos setup, but it has been suggested to me that Yahoo do not use greylisting at all. In the cases where I have noticed greylisting, the receiving mail server has been kind enough to include in the response that the message/IP has been greylisted.
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.
I was discovering that a flush of the queue shortly after seeing that the mail was being queued up was delivered with a success rate of about 90%. I'm really responding to this as an indication of someone who has been through the process of filling out the forms with Yahoo and for finally reaching what appears to be a resolution - after filling out the forms approximately 4 times over a period of 2 to 3 weeks the "problem" has been resolved and the mail is currently being accepted by the Yahoo mail servers[0]. As an aside, our advice to our clients who were having the issue at the time was to move off the Yahoo platform (in this case @xtra.co.nz addresses) Regards, Warren. [0] - By this I mean that we receive a 250 notice from the Yahoo mail servers, not that the mail is successfully delivered to the end-users mailbox.