By: Chris Reibold
Senior Email Analyst
While I did put considerable thought into titling this blog post “Yahoo breaks the internet!”, I thought that might be a little dramatic, but it was tempting.
Within the last 48 hours, Yahoo made a bold move in updating their DMARC policy setting to "p=reject." Therefore, mail containing a Yahoo from address is no longer considered legitimate if it does not contain an authentication signature, or if it did not come from properly identified Yahoo infrastructure.
What does this mean? If you are sending from a Yahoo address, to Yahoo users, your emails will always be bounced. Essentially, if the from address is @yahoo.com, and your message is not originating from Yahoo infrastructure (using their web interface, or sending with your Yahoo account from outlook, your iPhone, android, etc), it will never make it to the recipient.
If you look inside the SMTP logs of a message sent to Yahoo, it will look like this:
Message+not+accepted+for+policy+reasons.++See+http://postmaster.yahoo.com/errors/postmaster-28.html - - 0 0 0 SMTP - -
At JangoMail, we discourage our users from sending with a from address of major free email providers like Yahoo, Gmail, and Hotmail. With the new change, however, users will be flat out blocked if they try to send from a provider. While this move seems drastic, it will limit the amount of spoofed email to Yahoo accounts to zero.