Frequently Asked Questions
Find clear, technical answers regarding WHOIS and RDAP lookups, GDPR redactions, DNS diagnostics, SSL/TLS certificate verification, and API usage limits.
1. What is WHOIS and how does RDAP differ from legacy port-43 WHOIS?
WHOIS (RFC 3912) is the legacy directory protocol operated over TCP port 43 used to query registration records for domain names, IP address blocks, and autonomous system numbers (ASNs).
On January 28, 2025, ICANN officially sunset the requirement for generic top-level domain (gTLD) registries and registrars to maintain port-43 WHOIS, establishing RDAP (Registration Data Access Protocol) as the authoritative primary directory service. Unlike legacy WHOIS, RDAP delivers standardized, machine-readable JSON over HTTPS with internationalized domain name (IDN) support and native TLS encryption. For full protocol details, see our RDAP vs. WHOIS Technical Guide.
2. Why are registrant names and personal contact details redacted?
In compliance with global data privacy regulations (such as the European Union's GDPR) and ICANN's Registration Data Policy, registrars mask personal registrant details (name, physical address, direct phone, and personal email) by default in public RDAP and WHOIS output to protect individual privacy and reduce unsolicited spam.
Key technical attributes—including sponsoring registrar, creation timestamp, expiration date, EPP domain status codes, and authoritative nameservers—remain fully public. Law enforcement, intellectual property counsel, and cybersecurity analysts with a legitimate legal basis can request non-public data via ICANN's centralized Registration Data Request Service (RDRS).
3. How does Whoistrackr discover WHOIS and RDAP servers for any domain?
Our engine performs authoritative multi-tier bootstrapping. First, we query the official IANA RDAP Bootstrap Service to resolve the authoritative registry URL for the target top-level domain.
If a domain uses a legacy registry or country-code TLD (ccTLD) without RDAP support, our engine automatically contacts IANA at whois.iana.org to locate the authoritative root WHOIS server, queries the registry over port 43 with IP address pinning, parses referral endpoints, and inspects registrar records directly.
4. What is DNS propagation and why do records take time to update?
DNS propagation is the duration required for updates to resource records (such as changing an A record IP address or MX mail exchanger) to disseminate across recursive resolvers worldwide.
Every DNS record carries a Time-to-Live (TTL) value in seconds. Resolvers cache the record locally until the TTL expires before querying your authoritative nameservers again. While authoritative changes occur immediately at your nameservers, global recursive resolvers may retain cached entries for the duration of the previous TTL (typically 5 minutes to 48 hours). You can inspect live authoritative records using our Free DNS Lookup Tool.
5. How does the SSL/TLS Certificate Checker verify validity?
Our SSL Certificate Checker establishes a secure TLS handshake to port 443 of the target hostname and inspects the peer certificate presented by the origin server.
The tool parses Subject Alternative Names (SANs), the issuing Certificate Authority (e.g. Let's Encrypt, DigiCert, Cloudflare), cryptographic signature algorithms, certificate serial numbers, and validity timestamps. It calculates exact days remaining until expiration to help webmasters prevent costly TLS outages.
6. What HTTP response headers and security directives are analyzed?
Our HTTP Header Checker inspects origin web server responses, tracing HTTP status codes (200 OK, 301/302 redirects, 404, 500) and redirect chains up to 5 hops.
It analyzes critical modern security headers including Strict-Transport-Security (HSTS), Content-Security-Policy (CSP), X-Content-Type-Options, X-Frame-Options, and caching directives (Cache-Control, ETag).
7. What are the rate limits for free public lookups?
Free web lookups and unauthenticated REST API requests are allocated a sliding window limit of 30 requests per minute per IP address.
Every response includes transparent X-RateLimit-Limit and X-RateLimit-Remaining headers. If the rate quota is exceeded, the server returns an HTTP 429 Too Many Requests response with a standard Retry-After header. Higher volume allowances (300+ req/min) will be available in the upcoming Pro and API tiers (view proposed pricing).
8. Are my domain lookups private, logged, or shared publicly?
No. We do not publish, monetize, or publicly distribute user lookup queries. Lookups are executed live against authoritative registries and servers.
Diagnostic outputs are cached transiently for performance to protect authoritative nameservers from excessive queries. We do not front-run domain registrations or share query keywords with domain speculators. For more details, review our Privacy Policy.
9. How does the Bulk Domain Lookup tool work?
Our Bulk Domain Lookup Tool allows you to paste a list of domains or upload a CSV / TXT file. The engine validates each hostname against RFC 1035 standards, normalizes domain labels, inspects RDAP/WHOIS and nameservers in batch, and provides a one-click CSV export of domain status, registrar, and expiration dates.