What-is-DMARC?
Enter DMARC–Domain-based Message Authentication, Reporting & Conformance. DMARC was created to tell a participating receiving server what to do with a message that fails both SPF and DKIM validation. In other words, what to do if a message claims to be from you, but isn’t. DMARC standardizes how email receivers perform email authentication using the well-known SPF and DKIM mechanisms. This means that senders will experience consistent authentication results for their messages at AOL, Gmail, Hotmail, Yahoo! and any other email receiver implementing DMARCHow am I affected?
If you utilize a form on your website which has visitors send an email using a 'FROM' field in which they input their email addresses, there is a chance that the email will fail due to authentication if DMARC is being used by the @domain.com address. As of this writing, this only affects @yahoo.com addresses, however this may change in the future.
Note: Emails which are rejected due to the DMARC policy will normally indicate as much within the error itself. An example of an email rejected by Gmail can be seen below:
** abcdefg@gmail.com F=<hijklmn@gp.gptest.com> R=lookuphost T=remote_smtp: SMTP error from remote mail server after end of data: host gmail-smtp-in.l.google.com [173.194.77.27]: 550-5.7.1 Unauthenticated email from yahoo.com is not accepted due to domain's\n550-5.7.1 DMARC policy. Please contact administrator of yahoo.com domain if\n550-5.7.1 this was a legitimate mail. Please visit\n550-5.7.1 http://support.google.com/mail/answer/2451690 to learn about DMARC\n550 5.7.1 initiative. sd1si21689276obb.46 - gsmtp
What can I do to fix this?
We recommend that you update the 'FROM' field within your form to use an email address of @yourdomain.com. Additionally, the 'REPLY-TO' setting can be used with any DMARC compliant address and will successfully send emails without rejection such as @yahoo.com, @hotmail.com, @gmail.com, or @aol.com.
An example can be seen in the following header:
$headers = 'From: user@yourdomain.com' . " " .
'Reply-To: user@yahoo.com' . " " .
'X-Mailer: PHP/' . phpversion();
Additional Resources
The following articles are for reference only. Please note that Hostgator cannot offer direct support for the information provided below.
