Email authentication is the foundation of deliverability. Without proper SPF, DKIM, and DMARC records, your emails are far more likely to land in spam folders or be rejected outright. The good news is that Mailngine handles most of the heavy lifting for you, but understanding how these protocols work will help you debug issues and make informed decisions about your email infrastructure.
SPF (Sender Policy Framework) tells receiving mail servers which IP addresses are authorized to send email on behalf of your domain. When you add a domain to Mailngine, we provide you with an SPF include record that authorizes our sending infrastructure. You add this as a TXT record on your domain, and receiving servers will check it every time they get an email claiming to be from your domain. Keep in mind that SPF has a 10-lookup limit, so if you use multiple email providers, you'll need to be mindful of how many includes you're chaining together.
DKIM (DomainKeys Identified Mail) adds a cryptographic signature to every outbound email. Mailngine generates a unique 2048-bit RSA key pair for each domain you register. The private key stays on our servers and is used to sign the DKIM header of every message. The public key is published as a DNS record on your domain so receiving servers can verify the signature. This proves that the email hasn't been tampered with in transit and that it genuinely came from an authorized sender.
DMARC (Domain-based Message Authentication, Reporting, and Conformance) ties SPF and DKIM together with a policy that tells receiving servers what to do when authentication fails. We recommend starting with a policy of p=none so you can monitor reports without affecting delivery. Once you're confident that all legitimate email from your domain passes authentication, you can move to p=quarantine or p=reject. Mailngine's analytics dashboard shows your DMARC alignment rate so you can track your progress over time.