Email Security & DNS Misconfiguration Scanner
Check SPF, DMARC, DKIM, MX and MTA-STS for any domain — instant DNS audit
Email spoofing attacks exploit missing or misconfigured SPF, DMARC, and DKIM records. SentinelOSS queries DNS directly to audit your domain's email security posture — no login or API key required. Get an A–F grade with actionable fixes for every misconfiguration found, including DMARC policy enforcement level, SPF alignment, DKIM key detection across common selectors, MTA-STS enforcement, and BIMI brand indicator status.
How to use
- 1Enter any domain name (e.g. example.com). SentinelOSS queries DNS directly — no email access or account needed.
- 2SPF, DMARC, and MX records are checked instantly. DKIM is probed across 25+ common selectors.
- 3Each check is rated pass, warn, or fail with a score impact. The domain receives an overall grade A–F.
- 4Use the recommendations shown for each failing check to fix misconfigurations in your DNS provider.
Code & dependencies
What you installMachines
What you run it onWeb & domain
What you exposeSupply chain & AI
What you inherit📧Email / DNS~a few secondsReads: public SPF, DKIM and DMARC DNS records
Enter any domain name. SentinelOSS queries DNS directly to check your email security configuration — no login or API key required.
Try:
What we check
- ✓ SPF — authorised sending servers
- ✓ DMARC — policy & reporting
- ✓ DKIM — public key detection
- ✓ MX — mail server configuration
- ✓ MTA-STS — TLS enforcement
- ✓ BIMI — brand indicator