MX — where your mail goes
The servers that receive email for your domain. We also tell you which provider they belong to.
Free tool
Check your domain’s email security in seconds
Enter your company’s domain to see whether its SPF, DKIM and DMARC records are protecting you from spoofing and keeping your email out of junk folders — with plain-English results and what to fix first.
Nothing is stored. Works with any domain, not just ours.
What it checks
Four records that decide whether your email is trusted
Every one of these is public. Anyone — including the people trying to impersonate you — can look them up.
SPF — who may send
The list of servers allowed to send as your domain. We check there is exactly one, that it ends sensibly, and that it stays under the 10-lookup limit.
DKIM — signed mail
A cryptographic signature that proves a message came from you and was not altered. We look for keys on the selectors common providers use.
DMARC — your policy
Tells receivers what to do with mail that fails SPF and DKIM, and where to send reports. Without it, spoofing your domain is easy.
We also report MTA-STS, TLS reporting and BIMI if you have them. They are worth having, but are not needed for a good result. Need more detail on one record? Use the SPF checker, DMARC checker or DKIM checker.
Why this matters for a UK business
Since 2024, Google and Yahoo have required bulk senders to authenticate their mail with SPF, DKIM and DMARC, and Microsoft introduced similar requirements for Outlook.com in 2025. Mail from domains without them is increasingly likely to land in junk — including your invoices and quotes.
The bigger risk is impersonation. Without a DMARC policy, anyone can send email that appears to come from your domain: to your clients, asking them to pay a “new” bank account, or to your own finance team, apparently from a director. Invoice and payment fraud of exactly this kind remains one of the most common ways small UK businesses lose money.
If your results show problems, our guide to SPF, DKIM and DMARC explains how to fix each one. Every MyExchangeServer customer has all three set up and monitored for them as part of the service.
Questions
About the checker
What is the difference between SPF, DKIM and DMARC?
SPF lists the servers allowed to send email for your domain. DKIM adds a cryptographic signature to each message so receivers can tell it was not altered and really came from you. DMARC ties the two together, tells receivers what to do with mail that fails, and sends you reports. You need all three. Our plain-English guide to SPF, DKIM and DMARC goes through each one.
Why does the checker say no DKIM key was found when we have DKIM?
DKIM keys are published under a “selector” that each email provider chooses, and DNS has no way to list them. We check the selectors used by Microsoft 365, Google Workspace, Mailchimp, SendGrid and other common services. If your provider uses a different one, your DKIM can be working perfectly and still not show here. Your email provider can confirm it.
My DMARC policy is “none”. Is that bad?
It is a sensible first step but not a finished one. With p=none, receivers still deliver mail that fails DMARC, so it does not stop anyone spoofing your domain — it only gives you reports. Once the reports show your genuine senders all pass, move to p=quarantine and then p=reject.
Do you store the domains I check?
No. The lookup happens on demand and nothing about the domain is saved. To stop the tool being abused, we keep a short-lived counter keyed on a one-way hash of your IP address, which expires after ten minutes.
Is this the same as a full email security audit?
No — it checks the public DNS records that tell the rest of the internet how to treat your email. It cannot see how your mail server is configured, whether accounts use multi-factor authentication, or how well your filtering works. It is a quick, honest first look.
Results not what you hoped?
Send us the results and an engineer will tell you what to fix first. If you move your email to us, SPF, DKIM and DMARC are set up and monitored for you.
- Free assisted migration
- No set-up fee, no minimum term
- UK data centres, UK engineers