How to Set Up SPF, DKIM and DMARC (Without Getting Lost in the Acronyms)

If your domain sends any email at all - newsletters, receipts, password resets - it needs three DNS records to tell receiving mail servers "this mail really came from us." Without them, an increasing share of that mail lands in spam or gets rejected outright, especially at Gmail and Yahoo, which now require bulk senders to have all three in place.

SPF: who is allowed to send

An SPF record is a list, published in your DNS, of every mail server allowed to send email claiming to be from your domain. A receiving server checks the actual sending server against that list; anything not on it is a signal the mail might be spoofed.

DKIM: proof the message was not altered

DKIM attaches a cryptographic signature to outgoing mail, generated with a private key only your mail server holds. The receiving server checks that signature against a public key published in your DNS - if it matches, the message provably left your server unmodified.

DMARC: the policy that ties them together

DMARC tells receiving servers what to do when a message fails SPF or DKIM - quarantine it, reject it outright, or just let it through and report the failure back to you. It is also what most bulk-sender requirements are actually checking for.

Checking what you already have

Rather than guessing whether your existing records are correct, a lookup tool can pull all three at once and explain the DMARC policy in plain language instead of just showing the raw record.

Keeping it that way

These records can silently break - a DNS change made for an unrelated reason, an expired key, a renewed domain that lost its records in the process. Ongoing monitoring catches a regression the same day it happens rather than weeks later when deliverability has already dropped.