From what we can tell, its a type of "throttling" mechanism, perhaps intended to slow down problematic hosts.
We went back in our logs and found its been happening for weeks but at a low level, we never noticed until today. Today it got much worse, but even so, mail would trickle through to yahoo, one second we get the refusal and the next a few emails would be accepted. So I'm not sure they've fixed it, they may have toned it back down to the levels we saw from our older logs. At the time of writing this I think its better than it was earlier: spawn:/home/markjr/tmp# telnet mx1.mail.yahoo.com 25 Trying 64.157.4.78... Connected to mta-v22.level3.mail.yahoo.com. Escape character is '^]'. 220 YSmtp mta107.mail.sc5.yahoo.com ESMTP service ready quit and then the next second: 221 mta107.mail.sc5.yahoo.com Connection closed by foreign host. spawn:/home/markjr/tmp# telnet mx1.mail.yahoo.com 25 Trying 64.157.4.79... Connected to mta-v23.level3.mail.yahoo.com. Escape character is '^]'. 553 Mail from 216.220.40.247 not allowed - VS99-IP1 deferred - see help.yahoo.com/help/us/mail/defer/defer-02.html (#5.7.1) Connection closed by foreign host. Same deal on mx2, looks about 50/50 for a while, then blocks us out for a few minutes. It's definitely still happening, if I had to guess I'd say maybe its eased somewhat. -mark On Thu, 9 Oct 2003, Damian Gerow wrote:
Thus spake chuck goolsbee (chucklist@forest.net) [09/10/03 18:37]:
Indeed. They were blocking our servers this morning, but without any intervention by us (to my knowledge) it is working again now. Go figure.
Can someone from Yahoo! confirm that the borked blacklist has been fixed, and it's safe to remove the workarounds we've put in place?
-- Mark Jeftovic <markjr@easydns.com> Co-founder, easyDNS Technologies Inc. ph. +1-(416)-535-8672 ext 225 fx. +1-(416)-535-0237