crawler
DNS audit: resolver consensus
2026-06-21
How we classify domains (DNS_ALIVE/DNS_NXDOMAIN/DNS_PARKED/DNS_TRANSIENT) and why consensus eliminates false deaths.
ccTLD-aware resolvers: asking DNS where the domain lives
2026-06-22
What a ccTLD is, and why we pair a country-local resolver with a global one when auditing per-country domains.
recommendations
Upgrade TLS 1.2 to TLS 1.3
2026-07-06
Why TLS 1.3 is faster and safer than TLS 1.2 and how to enable it on common servers.
Legacy TLS version in use
2026-07-06
TLS 1.0/1.1 and SSL are deprecated and insecure; browsers block them. Upgrade to TLS 1.2+ immediately.
Serve the site over HTTPS
2026-07-06
Plain HTTP leaks traffic, loses referrer data, and hurts ranking. Redirect to HTTPS and canonicalize.
Add the missing security headers
2026-07-12
HSTS, CSP, X-Content-Type-Options, X-Frame-Options, Referrer-Policy and Permissions-Policy protect users at zero runtime cost.
Domain is parked (NS without A/AAAA)
2026-07-06
The domain has nameservers but no address records — it resolves nowhere. Point it at a web server.
No AAAA record — add IPv6
2026-07-06
The domain resolves only over IPv4. Adding an AAAA record keeps it reachable on IPv6-only networks.
DNS does not resolve (NXDOMAIN)
2026-07-06
Authoritative DNS says the name does not exist. The site is invisible until the zone is fixed.
Server responds with HTTP 5xx
2026-07-06
5xx means the server itself is failing. Find the crash or upstream timeout and fix it — every 5xx loses users and ranking.
Flatten the redirect chain
2026-07-06
More than one redirect hop wastes latency, crawl budget and link equity. Collapse chains into a single 301.