DMARC / SPF / DKIM Checker
Look up any domain's email authentication records. Checks DMARC policy at _dmarc.<domain>, SPF at <domain>, and DKIM at common selectors (default, google, selector1, etc).
Related reading
- DMARC, SPF, and DKIM explained (and why you need all three)Email spoofing is trivially easy without email authentication. Here's how SPF, DKIM, and DMARC work together — and how to check yours.
- How to read an open port (and when to actually worry)An 'open port' isn't a vulnerability by itself — it's information. Here's how to tell whether a port being open is fine, suspicious, or actively dangerous, and what to do about each case.
- How to check an SSL/TLS certificate (and what to look for)Every HTTPS site relies on a TLS certificate. Here's how to read one, what each field actually means, and the things that should make you suspicious.