At Simplelists we’ve long been conscious of the problems caused by forged email addresses. You will no doubt have seen such emails yourself, such as your banking supposedly informing you that your account has been suspended.
Over the years there have been a variety of technologies to combat the problem, including DKIM and SPF, which Simplelists has integrated into its services.
One of the newer technologies is DMARC. DMARC works slightly different to other solutions, in that it provides the facility to protect the actual "from" email address. This has been really important for companies such as Paypal, whose emails will never be sent or forwarded from anyone other than Paypal themselves.
As of yesterday though, Yahoo has now implemented the same solution. On the face of it, this would seem to be a sensible move. However, it now means that nobody other than Yahoo are able to forward Yahoo emails. This includes the "forward to your friend" function provided by news websites, as well as services by mailing list providers such as Simplelists.
So what is the way forward? Simplelists has a number of options, none of which are particularly attractive. If possible, we recommend avoiding the use of a Yahoo email address to send to any mailing lists. Other than that, the 2 main options are:
1. Reject emails to our mailing lists from Yahoo. With their change, Yahoo are effectively preventing their service from being compatible with mailing lists, so rejecting their emails as such is not an unreasonable option.
2. Rewrite the "from" email address of anyone who sends from a Yahoo email account. Of course, the disadvantage of this is that you won’t be able to see the email address of the sender, so we would likely add this information to the front of list emails. A messy solution, but it would at least allow Yahoo senders to still use email lists.
Please note that delivery to Yahoo email addresses is unaffected.
We hope that all makes sense. In summary, please avoid using Yahoo to send emails to our mailing lists. We’ll keep users informed of any updates, and if you have any questions or feedback, please contact us.