Tools and checklists
Email domain health check.
See if your email lands in the inbox or in spam, with plain fixes.
What the check looks at
Four DNS records decide whether your email lands in the inbox and whether others can fake it.
MX records
Where your email is delivered
The mail servers that receive email for your domain, and whether they answer.
SPF
Who may send email as you
One valid record, no more than 10 DNS lookups, and a strict ending such as ~all or -all.
DMARC
What inboxes do with fakes
A policy of quarantine or reject, full coverage and an address for reports.
DKIM
A signature on every email
A published key under the names Google, Microsoft and most hosts use.