What is up with email to Yahoo?

Some of our customers have experienced issues when sending mail to Yahoo addresses. The problem started about two weeks ago when Yahoo made a change to their email policies. Around October 16th, Yahoo started to 'greylist' almost every email that goes through their servers.

To understand what this means, we probably need to define some terms. Blacklist is a list of mail servers that are known to send spam. Whitelist is list of mail servers that are always accepted. In this case, a greylist is a term used to describe virtually every other server.

Yahoo is automatically deferring (read delaying) email they receive. The sending mail server is then required to resend the email until it goes through. It places a huge burden on the sending mail servers as they have to process the same piece of email again and again.

For example, if you send an email from your LTOL account to your friend at Yahoo, Yahoo automatically blocks our first attempt to send your email. Our LTOL mail server automatically tries to send your email again, an hour later. Generally the email is allowed through on the second or third request, sometimes up to four plus hours later. LTOL continues to try to send the email for up to 12 hours and will send you a warning if it takes more than three hours for your mail to go through.

Yahoo says they are doing this to try to block spam. They reason that spammers won't bother to send the same email more than once. Legitimate mail servers, like LTOL, will resend the mail until it goes through. The result is that delays are experienced in the delivery of legitimate email to Yahoo customers.

This new policy by Yahoo is being criticized loudly in the technical press as it unfairly burdens sending mail servers. It affects not just LTOL but the vast majority of mail servers worldwide.

We're sorry that our customers are having trouble sending email to Yahoo addresses and will continue to monitor this issue.