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Lifecycle & CRM

Email authentication (SPF, DKIM, DMARC)

Also known as: SPF · DKIM · DMARC · email sender authentication

Definition

Email authentication is the set of DNS records, SPF, DKIM and DMARC, that let a receiving mail server check that an email really came from the domain it claims and wasn't altered. Without them, mailbox providers can reject or junk legitimate campaigns.

SPF lists the servers allowed to send for a domain. DKIM adds a cryptographic signature that the receiver checks against a public key published in DNS. DMARC tells receivers what to do when those checks don't line up with the visible From address, and where to send reports. A common failure is a new sending tool, such as a newsletter platform, a CRM or a web form, added without its own records.

Since 1 February 2024, Google has required anyone sending more than 5,000 messages a day to Gmail addresses to use SPF, DKIM and DMARC, keep spam rates below 0.30 per cent and offer one-click unsubscribe on marketing mail, and it recommends staying below 0.10 per cent. Yahoo's rules, enforced from February 2024, require spam rates below 0.3 per cent, SPF and DKIM, a published DMARC policy and unsubscribes honoured within two days. Start DMARC in monitoring mode, read the reports until every legitimate sender passes, then tighten the policy. Send from your own domain, not a free webmail address.

More in Lifecycle & CRM

Churn rate

Churn rate is the percentage of customers who stop purchasing or cancel within a period. Revenue churn measures the value lost, which can differ sharply from the customer count lost.

Customer relationship management (CRM)

A CRM is software that records every contact, enquiry and deal in one place, with the owner, status and history of each, so sales, service and marketing work from the same facts. Its value comes from the process built into it, not from the tool.

Double opt-in

Double opt-in is a sign-up method where a person submits their details and then confirms by clicking a link, or replying, in a message sent to them. It proves the contact belongs to the person who gave it and that they agreed to receive marketing.

Email deliverability

Deliverability is whether sent email reaches the inbox rather than the spam folder or a block. It is governed by sender authentication, domain reputation and recipient engagement rather than content alone.

Lead magnet

A lead magnet is a free resource, such as a guide, checklist, calculator or sample, offered in exchange for contact details. It works when the resource solves a small, real problem and leads naturally to the paid service.

Lead nurturing

Lead nurturing is the planned follow-up that stays in touch with leads who aren't ready to buy yet, using useful messages over weeks or months until they're ready or drop out. It isn't a substitute for rejecting leads who were never a fit.

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