I have one customer that's been having trouble (not specific to him, all of our ISP subs send out via well-known gateways) and the message started off with "451 Message temporarily deferred - 4.16.50" and the most recent one was "Remote host said: 451 Message temporarily deferred - [190]". When I had this problem about 2 weeks ago I could manually initiate a connection to any of Yahoo's MX records and get the first error message. After I filled out the "Yahoo! Mail Feedback" form on their website (http://add.yahoo.com/fast/help/us/mail/cgi_defer/) I get this response four days later: ======================= Thank you for contacting Yahoo! Customer Care. There appears to have been an incident involving capacity issues within our delivery infrastructure. The error message "451 Message temporarily deferred - 4.16.50" indicates that our MTAs are currently experiencing heavy, unusual traffic. You may retry sending at a later time when you see this message. However please note that emails from the mail server(s) you are using may also have recently become deprioritized due to potential issues with its mailings. These deprioritizations were temporary but may be re-triggered if the sending IP profile continues to be poor. Typically, deprioritizations are triggered by bad individual sender or MAIL FROM profiles. ======================= Googling for some of these error codes yields this Yahoo discussion (http://tinyurl.com/y3nm6p) of a week ago that talks about greylisting and site upgrades, so hopefully this goes away sooner rather than later. Regards, Frank -----Original Message----- From: owner-nanog@merit.edu [mailto:owner-nanog@merit.edu] On Behalf Of chuck goolsbee Sent: Friday, November 03, 2006 3:42 PM To: nanog@merit.edu Subject: Re: Yahoo Postmaster contact, please

Greetings, NANOGers. I've got a mail cluster that's been spooling about 50000 messages for the past week or so (with very little drain and traffic passing), and my mail admin reports that attempted contacts to the Yahoo Postmaster are not getting answered. Can someone over there drop me a line off-list, please?

Welcome to a very NON-exclusive club Matt. You are not alone*. It seems as if every other mail server on the planet is having the same issue. As for an actual human being at Yahoo getting back in touch with you, I suspect I'll be refereeing a Flyers** vs Chiefs*** Ice Hockey game in hell before that happens. However, if an actual human being affiliated with Yahoo does get back to you prior to the Zamboni being delivered to the netherworld, please pass them over my way when your done with them. --chuck * http://www.forest.net/support/archives/2006/10/000792.php#000792 ** http://en.wikipedia.org/wiki/Philadelphia_Flyers#Broad_Street_Bullies *** http://en.wikipedia.org/wiki/Slap_Shot_%28film%29