WHOISEmail Tools
Check whether a domain's email will actually get delivered.
What are email tools?
Email tools check the settings that decide whether a domain's mail is delivered, trusted and protected from spoofing. Most of them live in DNS: SPF lists the servers allowed to send, DKIM publishes a signing key, DMARC sets a policy for failures, and MX records say where incoming mail goes. The email tools on this page read and explain those records, test a mail server's connection and check sending addresses against spam block lists.
They never send email, log in to mailboxes or ask for passwords.
What each email tool does
SPF Checker finds a domain's SPF record, breaks it into mechanisms and qualifiers, counts DNS lookups against the limit of 10 and flags common mistakes such as two records or +all.
DKIM Checker reads the DKIM key published for a selector you supply, showing the key type, key size, whether the key has been revoked and whether testing mode is on.
DMARC Checker explains a domain's DMARC policy, subdomain policy, percentage, alignment settings and reporting addresses, with problems and next-step recommendations.
Email Health Checker scores five weighted checks out of 100: valid MX records, a valid SPF record, a DMARC record, a problem-free DMARC record, and forward-confirmed reverse DNS for the first mail server.
SMTP Test connects to a mail server on port 25, 587 or 465, reads its greeting banner and lists the features it offers after an EHLO command, then disconnects.
Email Blacklist Checker checks a mail server's IPv4 address against SpamCop, Barracuda and SORBS and shows the result from each list.
When to use which email tool
Setting up a new email provider
Publish the records your provider gives you, then run the Email Health Checker for an overview. Use the DKIM Checker with the provider's selector, because DKIM is not part of the score.
Messages go to spam
Check the SPF Checker for errors and the DMARC Checker for alignment, then run your sending IP through the Email Blacklist Checker.
A device or website cannot send mail
The SMTP Test shows whether the server answers on the port you are using and whether it offers STARTTLS encryption.
Protecting a domain that never sends email
Publish a strict SPF record and a DMARC policy of reject, then confirm both with the SPF Checker and DMARC Checker.
How the email checks fit together
SPF, DKIM and DMARC work as a team. SPF and DKIM each prove something about a message, and DMARC asks receivers to check that at least one of them passes for the same domain shown in the From address. A domain with all three in place, plus correct MX records and reverse DNS for its mail server, gives receivers every reason to trust its mail.
Problems these email tools help solve
- Customers say your invoices land in their spam folder.
- Someone is sending fake messages that use your domain.
- A new newsletter service is not covered by your SPF record.
- A printer or contact form fails to send.
- Bounce messages mention a block list.
- A mail server's address has no reverse DNS name.
Related categories
Email depends on DNS and on the servers behind it. DNS Tools include MX Lookup and a DNS health check, IP Tools show who runs a sending address and its reverse DNS, and Domain Tools include risk signals that consider missing email protection.
Frequently asked questions
Which email records does every domain need?
A domain that sends mail needs one valid SPF record, DKIM signing set up with its provider, and a DMARC record. A domain that receives mail also needs MX records. A domain that never sends email should still publish a strict SPF record and a DMARC policy to stop spoofing.
Why is DKIM not in the Email Health Checker score?
DKIM keys are published under a selector name chosen by each email provider, and DNS offers no way to list them. Without the selector, the key cannot be found reliably, so it is left out instead of guessed. Use the DKIM Checker with your provider's selector.
Do these email tools send any messages?
No. They read public DNS records, check addresses against block lists and, in the SMTP Test, open a connection, read the server's greeting and send EHLO before disconnecting. No email is ever sent, no mailbox is accessed, and no password is requested or stored.
Why do my emails go to spam even though SPF passes?
SPF is only one signal. Receivers also check DKIM, DMARC alignment, the sending server's reputation and reverse DNS, and the content of the message. Run the Email Health Checker and the Email Blacklist Checker to find the weak spot, and make sure DKIM is set up.
Can I check a domain in the Email Blacklist Checker?
It checks IPv4 addresses, because block lists track the servers that send mail. Find your sending address in the headers of an email you sent. If you use a hosted service such as Google Workspace or Microsoft 365, the provider manages the reputation of its own servers.
Which SMTP port should I test?
Mail servers deliver to each other on port 25. Email apps, websites and devices should send through port 587 with STARTTLS, or port 465 with encryption from the start. Many networks block outgoing port 25, so a failure there is not always a fault.
What DMARC policy should I start with?
Start with p=none and a reporting address, so you can see who sends mail as your domain without affecting delivery. Fix SPF and DKIM for every genuine sender, then move to quarantine and finally reject. Only quarantine and reject actually stop spoofed messages.