The Authentication Trinity: A Technical Guide to DMARC, SPF, and DKIM Implementation

Let's be honest: SPF, DKIM, and DMARC aren't the most exciting topics in the world. But since Google and Yahoo updated their requirements in 2024, they've become the most critical. If you don't have these three set up correctly, we've found that your chance of hitting the inbox is effectively zero.

We handle a lot of the heavy lifting for you at GetMailer—like managing DKIM keys and ARC signing—but I think it’s important for you to understand the "Trinity" that protects your brand.

Our Guide to the Pillars

Think of SPF as your authorized caller list. It’s a simple DNS record that tells the world which IPs we’re using to send your mail. We keep this updated so you don't have to worry about the dreaded "10 lookup limit" that breaks so many records.

DKIM is where we get into the digital signatures. We sign every email with a private key, proving that the content hasn't been messed with. Because we handle the key rotation for you, you get the security of 2048-bit encryption without the manual headache.

Then there’s DMARC—the boss of the operation. This is where you tell ISPs what to do if the other two fail. We always recommend starting with p=none so we can monitor your reports together before moving to a strict reject policy.

The Extra Step We Take: ARC

One problem we spent a lot of time solving is what happens when your email gets forwarded. Forwarding often breaks SPF. That’s why we integrated ARC (Authenticated Received Chain). It allows us to preserve the authentication results across multiple "hops," ensuring that your brand’s trust travels with the message, no matter how many times it’s redistributed.

We’re In This Together

Our goal at GetMailer is to make the technical "boring" stuff invisible so you can focus on your content. But we also want to empower you with the right infrastructure. By getting the Trinity right, we’re not just avoiding spam filters; we’re building a foundation of trust with the world’s biggest inbox providers.