RSDN·Check: free domain security check

Find out whether someone can send email pretending to be you, and whether your domain and website are set up securely. Enter a domain to check:

• Email spoofing protection: SPF (including the 10-lookup limit), DKIM, DMARC, MTA-STS and TLS reporting, with fixes for Google Workspace, Microsoft 365 and other providers.
• Domain and DNS: IP addresses, DNS host, DNSSEC, CAA and whether www works.
• Website security: HTTPS, the HTTP-to-HTTPS redirect, HSTS, Content Security Policy and other security headers, cookie flags and security.txt.
• Platform and software: WordPress version, plugins and theme compared with the latest releases, PHP support status, and hosted platforms such as Squarespace, Wix and Shopify.

Is it safe to check a domain I don't own?

Yes. The checker only looks at public DNS records and loads the homepage and a few standard public files, the same way a browser would. It never scans ports, tries to log in or probes for vulnerabilities.

Do you store the domains I check?

No. DNS lookups go from your browser to Cloudflare's public DNS resolver, and the website checks run on our server, which doesn't store or log the domains you check.

Built by Arsydian, IT services in Charlotte, NC.