SPF, DKIM and DMARC: set up your sending domain

The three records

• SPF lists the servers allowed to send for your domain. Google Workspace: include:_spf.google.com. Microsoft 365: include:spf.protection.outlook.com.
• DKIM signs each email. Turn it on in the Google Admin console (Apps → Google Workspace → Gmail → Authenticate email) or in Microsoft Defender (Email authentication settings → DKIM).
• DMARC tells inboxes what to do when SPF or DKIM fail. Start with v=DMARC1; p=none; rua=mailto:you@yourdomain.com, then move to p=quarantine once reports look clean.

Check it in the app

Mailboxes → Check a domain looks up SPF, DKIM, DMARC and MX for any domain and tells you exactly what's missing. DNS changes can take up to an hour to show.

Sending habits that help

• Keep each mailbox to 30 to 50 cold emails a day, and add mailboxes rather than raising limits.
• Write plain, short emails; avoid links and attachments in the first one.
• Consider a separate domain for cold email, so your main domain's reputation is protected.
• Keep the do-not-contact list up to date and honour every opt-out.