Documentation
High-level documentation for the tools available on PublicDNS.nl.
Overview
The multi tool exposes several independent checks that you can run via the web interface. Most tools also provide an “Advanced” mode showing the raw JSON response that could be reused for API integrations. (If you plan to build an official API on top, you can expand this section with concrete endpoints and examples.)
Tools
SSL Check
The SSL tool connects to hostname:443 and retrieves the
leaf certificate and chain. It shows:
- Expiry date and days remaining
- Subject and issuer (CN)
- TLS protocol and cipher
- SHA-256 fingerprint
- Subject Alternative Names (SANs)
- Chain certificates (CA / intermediate / root)
DNS tools
- DNS Record Lookup: A, AAAA, MX, NS, TXT, CNAME
- Reverse DNS (PTR): IP → hostname mapping
- DNS Health: summary for A, AAAA, MX, NS
- DNSSEC Check: simple indicator for DNSKEY and RRSIG
Email tools
- Email Authentication: SPF, DMARC, CAA presence
- SPF Validator: structure and common issues
- Mail Delivery Checklist: MX, IPs, PTR, SPF, DMARC
HTTP & uptime
- Uptime Check: HTTP status, response time
- HTTP Headers: response headers + security headers
- Redirect Trace: hop-by-hop redirects and final URL
Security Score
The Security Score combines:
- SSL/TLS status
- DNSSEC status
- Email authentication (SPF/DMARC/CAA)
- HTTP security headers
The result is a score from 0–100 and a letter grade (A–F), intended as a quick, non-exhaustive indicator of overall hygiene.
Advanced JSON
For each tool, you can switch the output from Simple to Advanced. The advanced view shows the raw JSON payload returned by the backend. This can be useful if you want to:
- Debug specific edge cases
- Copy structured data into other tools
- Prototype your own scripts around the same logic