60% of listed companies score a D or F on email authentication.
Resolve, audit and monitor your DNS records and SPF, DKIM, DMARC, MTA-STS, BIMI and DNSSEC protocols from a single dashboard.
Host your email security policies, get alerts as soon as an anomaly appears and generate shareable reports for your clients.
64+ free tools, 18 resolvers across 4 continents, results in seconds.
Auto-detection - matching tools will appear below
Aggregated data since 2025
Measured over the last 12 months
Alerts sent as soon as a difference or latency anomaly is detected
Diagnose your DNS zones and email authentication, host your security policies and monitor everything continuously.
Enter a domain, get a complete verdict on DNS and email authentication. Overall score, identified errors and fixes to apply.
Run an auditMTA-STS, BIMI and DMARC/TLS-RPT monitoring without infrastructure to manage. Activate your policies in a few clicks.
Discover hostingContinuous DNS alerts, aggregated DMARC and TLS-RPT reports, change detection and latency anomalies.
Enable monitoringType your domain name and pick one of the 64+ available tools.
CaptainDNS queries 18 resolvers across 4 continents and analyses your DNS, SPF, DKIM, DMARC, MTA-STS, BIMI and DNSSEC records.
Every issue detected comes with a clear explanation and a ready-to-paste corrected record.
All tools are free. Plans add volume, retention, and API access.
Paste raw email headers and get a detailed report on authentication, delivery path and spam verdict.
Full scan of SPF, DKIM, DMARC, MTA-STS, BIMI, DANE and DNSSEC in a single pass. Overall score, per-protocol verdict and fixes to apply.
Redirect any domain with automatic HTTPS. Define per-path rules (exact, prefix, regex), import via CSV, and track traffic in real time with the analytics dashboard.
Automatic HTTPS
TLS certificates issued and renewed automatically via Let's Encrypt.
SEO Redirect Map
Per-path rules with exact, prefix, or regex matching. CSV import.
Real-time statistics
Hits, unique visitors, 404s, top referrers, countries, and paths.
301 and 302 redirects
Permanent for SEO or temporary for campaigns.
Path forwarding
Preserve URL paths and query strings during redirection.
Apex and subdomains
Root domains via A/AAAA and subdomains via CNAME.
1 600+ listed companies across 16 stock indices, analysed weekly on 8 protocols. 60% score a D or an F.
Protect the sending reputation of your campaigns. Audit deliverability, monitor DMARC and TLS-RPT reports, and spot blockers before your recipients do.
Enable DMARC monitoringHarden email authentication across all your domains. Deploy MTA-STS, DNSSEC and DANE, then continuously monitor DNS changes.
Deploy MTA-STSAudit your clients' domains in seconds. Generate shareable reports and demonstrate the value of every fix.
Analyze a client headerCaptainDNS · May 11, 2026
GPTBot, ClaudeBot and PerplexityBot do not follow redirects like Googlebot. Understand their actual behavior to stay visible in ChatGPT, Claude and Perplexity.
CaptainDNS · May 4, 2026
Phishing targets the masses, spear phishing targets the person. In 2026, AI, OSINT, and deepfakes blur the line. Full breakdown with real cases and defenses.
CaptainDNS · April 24, 2026
HSTS (RFC 6797) forces browsers to contact your site only over HTTPS. This guide covers the protocol, the directives, per-stack configurations and how to submit to the Chrome preload list.
You manage DNS zones, you debug deliverability issues or you secure email authentication for your clients. CaptainDNS gives you answers in seconds, with clear explanations of what needs to change and why.
18 resolvers spread across 4 continents reproduce what your recipients actually see. If a resolver in Frankfurt, Sydney or Montreal gets a different answer, you know immediately.
Stay in control of DNS and deliverability with actionable explanations. Here are the answers to the most common requests.
Send a test email and instantly check SPF, DKIM, DMARC, spam score and inbox placement.