MX, SPF, DKIM and DMARC in plain English
Business email uses several records with different jobs. MX directs incoming messages. SPF identifies permitted sending systems. DKIM adds a verifiable signature to outgoing messages. DMARC checks alignment with the visible sender domain and publishes a policy for authentication failures. These work together; one does not replace the others.
Before you start
- List every service sending as your business, including forms, newsletters and invoices.
- Identify the provider that manages your domain’s DNS.
- Obtain current setup guidance from each actual email supplier.
What to do
Separate receiving from sending
Being able to receive an email confirms a different route from sending a form notification. If one fails, record which direction and which tool is affected. Do not replace MX records simply because a website’s outgoing message is missing.
Map the approved senders
Write down the mailbox provider and other tools authorised to send business messages. Your administrator needs the complete list before reviewing SPF or DKIM. An overlooked booking or invoicing service can matter even if your normal email application works.
Have the configuration reviewed together
Ask the administrator to compare the live records with provider instructions and inspect an authorised test message’s authentication results. DMARC policy changes should follow that review, so a stricter policy does not unexpectedly reject legitimate business mail.
Keep a record for future changes
Save the approved provider list and the date of the review in your private business records. Repeat the check when adding or removing a sending tool. Keep the sending service’s own account and verification active; DNS text alone does not create a mailbox.
What to check
- Each legitimate sender has been considered, not just the main inbox.
- Incoming and outgoing tests have distinct results.
- You know who reviews future email-tool changes.
Sources and further reading
Platform features can change. Check the provider’s current guidance before changing a live service.