SPF
Lists the servers allowed to send mail for your domain.
Without it: Anyone can send mail as you, and receiving servers trust your real mail less.
Free tools
Free domain security checkup
See why messages land in spam, get rejected, or can be spoofed. We read your SPF, DKIM, DMARC, MX, and nameservers, then show the fix for each. Free with an account.
Free with an account · results in seconds · no card. The domain you enter is shared with the NHM team so we can follow up if you'd like help. Stuck? Ask us.
Nameservers
SPF Records
DKIM Authentication
DMARC Policy
MX Records
What the checkup reads
Five records decide whether your email is trusted.
The checkup reads public DNS, the same records every receiving mail server reads before deciding what to do with your message. Nothing is installed and nothing on your domain changes.
DKIM
A signature that proves a message left your provider unaltered.
Without it: Providers cannot verify your mail is really yours, so more of it is filtered.
DMARC
Your instruction for mail that fails SPF or DKIM: reject it, quarantine it, or let it through.
Without it: Spoofed mail using your name is delivered, and you never hear about it.
MX records
Where mail sent to your domain is delivered. We recognize Microsoft 365 and Google Workspace and show the steps for the provider you actually use.
Without it: Mail to your domain bounces or goes to the wrong place.
Nameservers
Who answers DNS for your domain, which is where every fix above gets made.
Without it: You cannot change any record, and a DNS outage takes email and website down together.
Want the whole website checked?
The free IT checkup runs this plus HTTPS, security headers, exposed files, reputation, and registration.
Run the full checkupAfter the checkup
What a free account adds.
A free DomainGuard account
- The full record text and step-by-step fixes, written for the DNS provider you actually use
- Re-check after a DNS change, with results kept so you can see what moved
- One email address watched for dark-web breaches, re-checked on a schedule
- The same report in the DomainGuard iPhone app, with a push when a breach lists your email
On Starter and up
- DMARC reports: every service and server actually sending as your domain, legitimate or not
- Daily re-checks of your records without you asking, with an alert when one changes
- More monitored inboxes for the breach watch
Questions
About the checkup.
- What email records does the checkup look for?
- The checkup reads your SPF, DKIM, and DMARC records, your MX records, and your nameservers. SPF, DKIM, and DMARC are the three authentication standards that tell receiving mail servers your domain is authorized to send email and what to do with suspicious messages.
- What happens if my domain is missing SPF, DKIM, or DMARC?
- Without these records your emails are more likely to land in spam, get rejected, or let attackers spoof your domain and send fake mail pretending to be you. The report explains each issue and which record controls it.
- Do I need an account to run the checkup?
- For the full checkup, yes: a free account, no card, and it keeps your results so you can re-check the same domain after a DNS change. It checks any domain. The deeper checks that probe the site itself (open ports, exposed files, known vulnerabilities) run once you verify you own the domain, which takes about a minute.
- Who do I contact if the report shows problems?
- Use the report as a checklist and share it with whoever manages your email or domain: your IT team, web host, or email provider. The signed-in report shows the exact record text and the steps for your DNS provider. If you need hands-on help, contact NHM Ohio directly from the page.
- How long does it take for DNS changes to take effect?
- Most DNS changes propagate within a few hours, but can take up to 48 hours. After updating your records, run the checkup again to confirm everything looks correct.
Talk directly with the owner
Need help fixing email security issues?
Contact us today to learn how we can help you configure SPF, DKIM, and DMARC records to improve email authentication and reduce common deliverability problems.