Business Email on Your Domain: SPF, DKIM and DMARC
Understand the DNS records that help receiving mail systems verify messages sent from your business domain.
Start with the provider’s setup instructions
Business email uses DNS records to route and authenticate mail. Before editing DNS, list every service that sends mail for your domain, such as your mailbox provider, website forms, invoicing system or newsletter platform. Missing a sender can affect legitimate messages.
What SPF, DKIM and DMARC do
SPF identifies systems authorised to send mail for a domain. DKIM adds a cryptographic signature that a receiving system can verify. DMARC lets a domain owner publish how receivers should handle messages that fail checks and receive reports, subject to provider support.
Make DNS changes carefully
Use the exact hostnames and values supplied by each provider. Avoid creating multiple SPF records for the same domain, and coordinate changes with whoever manages your DNS. DNS updates can take time to appear, and an incorrect record may disrupt mail delivery.
Monitor before tightening policy
Test messages from all authorised services and review DMARC reports if enabled. Start with a monitoring policy where appropriate, identify legitimate sources, then decide whether to move to stricter handling. Keep a record of the old values so changes can be rolled back.
Frequently asked questions
Will SPF, DKIM and DMARC guarantee inbox delivery?
No. Authentication helps receivers assess a message, but delivery also depends on recipient policies, sender reputation, message quality and other technical factors.
Can I configure these records without affecting email?
Changes can affect mail if records are incorrect or omit a sender. Inventory your mail services, follow provider instructions and test messages after each DNS change.
