If you use our mail forwarding service to forward mail to a Gmail account, then you may have occasionally had problems receiving mail from domains that have restrictive SPF or DMARC policies. What's happenning there is that when Gmail looks up the DNS records for the sending domain it sees that Opalstack's mail system is not allowed to send mail for that domain, so Gmail would reject the message.
In the past, our recommended workaround for this problem was to deliver mail to an Opalstack mailbox instead of using forwarding and then retrieve mail into Gmail via POP3. That works OK, but there are a lot of extra setup steps and a polling delay before your mail would actually arrive at Gmail.
The number of rejections of this type have recently increased due to Gmail tightening up their SPF and DMARC requirements. To compensate for this and to hopefully resolve these forwarding problems once and for all we're configuring our forwarding MX servers to use the Sender Rewriting Scheme, aka SRS, to rewrite the return path on forwarded messages. Once that's done, the recipient servers will check SPF and DMARC for the forwarding server instead of the original sender's domain and the message should then be accepted.
We'll deploy the feature on 17 February 2024 at 0500 UTC on half our MX servers and monitor them for a few days. If there are no issues then we'll deploy it to the rest of the MX.
We anticipate no disruptions to mail service and no action is required from customers other than to enjoy improved mail delivery 🎉
