VISI | Announcements | Difficulty sending mail to yahoo.com or aol.com?I ran into a variant of this problem with Gmail. I was redirecting an unfiltered email stream to Gmail, and when I read the mail in Gmail I "marked" the spam. Alas, Gmail looks at the redirect as the source of the email, so the more I marked as spam the lower the reputation of the redirector fell. Over time Gmail marked more and more valid emails as spam, and missed more and more spam. I fixed it by filtering the mail stream, and never marking anything that was redirected as spam (I just delete it).
Over the past weeks, it appears that Yahoo has begun grey-listing all (or most) incoming mail. This means that they are rejecting the first mail delivery attempts and telling sending servers to try again later. Yahoo also appears to be grey-listing with content filters. In this case, customers may see the error message: message text rejected by mx1.mail.yahoo.com: 451 This message indicates that suspicious content was detected, but that the sending server may try again.
For mail grey-listed automatically or by IP, users may see: : connect to x.mx.mail.yahoo.com[209.191.aaa.xxx]: server refused mail service You may also see error code 421 in the error response.
Generally, this email is also being retried, however, if retried too soon, it will be rejected again. It may even be rejected permanently by Yahoo with no change in error message that we have found. Yahoo's documentation claims that they are not grey-listing, but instead are filtering mail based upon the sending server's compliance with standard mail practices. Our servers, however, are compliant, but we are still seeing significant deferrals. Yahoo is also testing DomainKeys verification, which we are reviewing to potentially mitigate the problem. There appears to be no way to contact Yahoo about this except via web forms that do not generate any response except confirmation of receipt. We recommend that any users forwarding email to yahoo.com addresses cease forwarding or redirect to another location.
Of course, this affects not only customers forwarding mail to Yahoo, but ANYONE attempting to send mail to Yahoo addresses.
AOL AOL uses an automated system to block mail from potential spam sources. When mail is reported as spam by users, the IP addresses for servers used to transmit the mail are recorded, and, once their limit has been reached, IP addresses are blocked from sending mail to AOL for 24 to 48 hours. This can be exacerbated by VISI customers forwarding email to their own AOL accounts and then reporting any forwarded spam, which can result in temporary blocks of VISI mail server IP addresses. The automated system is COMPLETELY automatic, and no intervention is possible in expediting removal of IP addresses. Unfortunately, this will affect ANY customer attempting to send to AOL addresses, not just forwards to AOL accounts. As with Yahoo, above, we recommend that any users forwarding email to aol.com addresses cease forwarding or redirect to another location.
The Yahoo and AOL bizarre responses to the spam deluge tells us how dire their financial situations are, but I must also say that Visi should have figured out DomainKeys a year ago. Maybe Yahoo is doing this in part to force adoption of DomainKeys; too bad their execution is incompetent.
In the meantime, encourage anyone you know who's still using Yahoo or AOL to get out fast and switch to Gmail.
Update 12/21/06: There's a good defensive strategy for those of us still using SMTP services (non-webmail) btw. Get a Gmail account and configure your dedicated email client to use Gmail's smtp service. If Google is your sending service, I suspect Yahoo and AOL won't be blacklisting the sending domain.