What SPF, DKIM, and DMARC do
- SPF lists the mail systems allowed to send on behalf of a domain. Add the provider’s approved sender to the existing SPF record; do not create a second SPF record for the same hostname.
- DKIM lets a receiving service check a cryptographic signature attached to a message. Your email provider supplies the DNS record or records to publish.
- DMARC tells receiving services how to handle mail that fails authentication checks and provides a way to receive reports. Set it up with the domain owner, check every legitimate sender, and choose an enforcement policy only after reviewing the reports.
Follow the exact DNS values and hostnames shown by your provider. If several services send mail from the same domain, coordinate their records instead of pasting in overlapping or duplicate instructions.
Mailbox providers set their own requirements
Google and Yahoo publish sender guidance that can change. Google’s current guidance calls for authentication, valid sending infrastructure, and easy unsubscribe options; higher-volume senders have additional SPF, DKIM, DMARC alignment, and one-click unsubscribe requirements. Read the Gmail sender guidelines and Yahoo sender best practices before a large campaign.
Permission and list hygiene matter
Send to people who understand what they signed up for. Keep the signup source and consent wording, remove hard-bounced addresses from future sends, and preserve unsubscribe and complaint records as suppression entries. Do not buy or scrape a list, and do not re-import a person who has opted out just because a new spreadsheet contains their address.
Build a repeatable sending routine
- Authenticate the domain using the records supplied by your email provider.
- Test the From name, reply address, links, and unsubscribe route before a campaign.
- Send on a cadence that matches the signup promise and your ability to provide useful content.
- Review bounces, complaints, unsubscribes, and click activity after each send.
- Investigate sudden changes before increasing volume or changing multiple settings at once.
What deliverability does not mean
Authentication confirms aspects of the sending domain; it does not prove that a message is wanted, guarantee that it reaches the inbox, or make a purchased list acceptable. Inbox placement depends on many signals controlled by senders, recipients, providers, and mailbox services.
For list permission and signup records, see our permission-based growth checklist. For platform-specific limits, compare the MailerLite review with the alternatives.