Guides

Plain-English explainers for the DNS records behind email security — what each one does, how it's structured, and how to set it up. Each guide pairs with a free checker.

DMARC, explained — and how to set it up

DMARC is the record that actually stops people spoofing your domain. Here's how it works and how to roll it out safely.

SPF records, explained — and how to set one up

SPF lists the servers allowed to send email as your domain. Get it right and your mail stays out of spam; get it wrong and it can make things worse.

MTA-STS, explained — and how to set it up

MTA-STS forces other servers to deliver mail to you over an encrypted connection — closing the door on downgrade attacks.

BIMI, explained — and how to set it up

BIMI puts your brand logo next to authenticated email in the inbox — a trust signal you only earn once your authentication is solid.

DNSSEC, explained — and how to enable it

DNSSEC signs your DNS so answers can't be forged in transit — protecting your mail and website from redirection.

DKIM, explained — and how to set it up

DKIM cryptographically signs your outgoing mail so receivers can prove it's genuinely from you and wasn't tampered with.

Google & Yahoo sender requirements — the checklist

Since 2024 the big mailbox providers enforce a baseline for senders. Here's exactly what they want and how to meet it.

SPF vs DKIM vs DMARC — what's the difference?

Three records, three jobs. Here's what each one does, why one isn't enough, and how they work together.

DMARC p=none vs p=quarantine vs p=reject

The DMARC policy tag decides whether you're monitoring or actually protected. Here's how to move up safely.

How to set up DMARC for Google Workspace

The exact SPF, DKIM and DMARC steps for a Google Workspace (Gmail) domain — including the Admin console bits people miss.

How to set up DMARC for Microsoft 365

The exact SPF, DKIM and DMARC steps for a Microsoft 365 domain — including the two DKIM CNAMEs Microsoft uses.

How to set up DMARC for Zoho Mail

The exact SPF, DKIM and DMARC steps for a Zoho Mail domain — including the DKIM selector step in the Admin Console.

How to set up DMARC for Amazon SES

SES is a relay, so alignment is everything. Here's how to get DKIM and SPF aligned to your domain and enforce DMARC.

How to set up DMARC for Mailchimp

Mailchimp authenticates with CNAME-based DKIM aligned to your domain. Here's how to set it up so campaigns pass DMARC.

How to read a DMARC aggregate (RUA) report

DMARC reports are how you find out who is really sending email as your domain — but providers send them as compressed XML. Here's what's inside and how to actually read it.

How to check if your domain or mail IP is blacklisted

A single blacklisting can silently stop your email reaching inboxes. Here's how DNS blacklists work, how to check whether you're on one, and what to do if you are.

Fixes & troubleshooting

Why is my email going to spam?

The real causes and a step-by-step checklist to get back to the inbox.

Fix SPF “too many DNS lookups” (PermError)

What the 10-lookup limit means and five ways to get under it.