Letrago

Check MX, SPF, DKIM and DMARC

See whether a domain's email is set up correctly to deliver messages and prevent spoofing.

✓ Free, no sign-up

How it works

SPF states which servers may send email for the domain, DKIM signs each message and DMARC tells receivers what to do when those checks fail. Since 2024 Gmail and Yahoo require SPF, DKIM and DMARC from bulk senders. DKIM uses a "selector" only the sender knows, so we try the most common ones.

How to use it, step by step

  1. Enter your email domain (what comes after the @).
  2. We check your MX, SPF, DKIM and DMARC records.
  3. You'll see what's fine, what's missing and the recommended setup.
  4. Add or fix the TXT records in your domain's DNS.

What it's useful for

  • Keep your emails out of the spam folder.
  • Stop others from sending fake emails as your company.
  • Review your setup after switching email providers.

FAQ

My emails land in spam — where do I start?

Make sure you have a single SPF record that includes all your sending services, enable DKIM with your email provider and publish DMARC, even if you start with p=none to receive reports.

Which DMARC policy should I use?

Start with p=none and a rua address to receive reports. Once you confirm all your legitimate email passes, move to quarantine and then to reject.

What is SPF?

A TXT record listing which servers may send email for your domain. There must be only one per domain.

What is DKIM?

A digital signature your provider adds to each email to prove it wasn't altered. You enable it in your provider's panel and publish it in DNS.

Why does my mail go to spam if I have SPF?

Today you need all three: SPF, DKIM and DMARC. Gmail and Yahoo require them from bulk senders.

What is SPF's 10-lookup limit?

An SPF record can't trigger more than 10 DNS lookups (include, a, mx…). Going over makes it fail, so keep it simple.