Infrastructure and authentication
Infrastructure and authentication is the technical aspect of deliverability. It’s a number of configuration settings that allow the email providers to check if the message was sent by the person who identified themselves as the sender. It might sound a little crazy, but it’s actually almost as easy to spoof
an email sender address as it is to write a wrong sender on a snail mail envelope.
Email spoofing can be easily achieved with a working SMTP server and mailing software like Outlook or Gmail. Once an email message is composed, the scammer can forge fields found within the message header such as the FROM, REPLY-TO and RETURN-PATH addresses. After the email is sent, it will appear in the recipient’s mailbox that appears to come from the address that was entered.
Email providers have created three safeguards that allow them to check if the email message was sent from the same domain as the sender’s email address to prevent spoofing.
ReturnPath has a good glossary
of these settings:
SPF Record: SPF, which stands for Sender Policy Framework, describes a list of IP addresses that are allowed to send emails from a specific domain.
DKIM: DKIM stands for Domain Keys Identified Mail and is the next stage of Domain Keys. DKIM uses a pair of cryptographic keys, one private key that all outgoing messages are signed with and one public key that is published in DNS.
DMARC: DMARC, or Domain-based Message Authentication, Reporting & Conformance, standardizes how mailbox providers authenticate and deliver mail by utilizing existing SPF and DKIM records. Senders can indicate if their emails are protected by SPF and/or DKIM, and tell receivers to junk or reject a message if neither of those authentication methods passes.
There’s a nice tool that let’s you check whether everything is configured correctly: http://www.mail-tester.com
. When you go to their site, mailtester will give you an email address. If you send a preview of your newsletter to that address, mailtester will check your configuration settings and give you a report with a score: