Originally when we launched in 2013, we asked users not to forward to major services like Google. They don't like it, they don't want to receive it, and they block us because you do it. Fast forward to today and only one thing has changed: We've gone out of our way to accommodate your forwarding needs as best we can. The other side, however, still doesn't want it or like it. Although we've done our best to help, and will continue to do so, we will also continue to advise against the practice because of that simple fact: They don't want it, and they will fight back against it.
Today we bring you another reason not to forward. We've been reviewing emails rejected by Google, and we've found a strong theme. Here is a sample from our logs:
Jun 7 09:46:35 Server22734-me postfix-110/smtp[21776]: 61D21CBD0559: to={removed}@gmail.com, relay=gmail-smtp-in.l.google.com[74.125.21.26]:25, delay=1.7, delays=0.65/0.01/0.33/0.68, dsn=5.7.1, status=bounced (host gmail-smtp-in.l.google.com[74.125.21.26] said: 550-5.7.1 Unauthenticated email from ymail.com is not accepted due to domain's 550-5.7.1 DMARC policy. Please contact the administrator of ymail.com domain if 550-5.7.1 this was a legitimate mail. Please visit 550-5.7.1 https://support.google.com/mail/answer/2451690 to learn about the 550 5.7.1 DMARC initiative. a17si725522ywa.360 - gsmtp (in reply to end of DATA command))
This was a forwarded email from ymail.com. However, if you look above this in the logs, you'll see that we did everything right:
Jun 7 09:46:34 Server22734-me postfix-110/qmgr[8285]: 61D21CBD0559: from=<SRS0=kR35do=UG=ymail.com={recipient}@{client_domain}>, size=63260, nrcpt=1 (queue active)
We used SRS, and nested "ymail.com" in the sender with the client domain at the end. But Google still rejected it for DMARC, because SRS is not about updating the actual "From" field in the headers. Therefore, Google has chosen to respect DMARC over SRS. Google does not want your forwarded emails. When forwarding to them, you absolutely must forfeit some of the email you receive, and it is 100% in their hands.
We will continue to do our best to support your forwarding habits, but please understand that you have stacked the deck against yourself if you've chosen this path, and that any resulting lost emails are a direct result of your decision to do so. Please be careful with the decisions you make, we can only do so much to help you to force another email provider to work how you want it to.
On a side note, we recognize that a lot of people respond to this with "Well it works fine for me, so it must be you." The truth is, it works fine for almost everyone. Most people get away fine without receiving emails from the domains that specify reject in their DMARC record. By our last check, 32 emails out of 5588 were rejected by Google for the above mentioned conditions. This only impacted 18 customers, and they probably didn't realize or care about the missed emails. However, one customer not receiving one important email should be enough to make anyone stop and say "This is important, listen up."