Infrastructure
· 9 checks — DNS, redirects, IPv6, crawlability, URL variants, and domain intelligence rolled into one auditable list.DRedirect ChainAction2 redirect(s), 3032 ms totalFIX
https://cwi.nl
613 ms · HTTP/1.1
https://www.cwi.nl/
974 ms · HTTP/1.1
https://www.cwi.nl/en/
1445 ms · HTTP/1.1 FINAL
| # | URL | Status | Time | Protocol | Server |
|---|---|---|---|---|---|
| 1 | https://cwi.nl | 301 | 613 ms | HTTP/1.1 | nginx |
| 2 | https://www.cwi.nl/ | 302 | 974 ms | HTTP/1.1 | nginx |
| 3 | https://www.cwi.nl/en/ | 200 | 1445 ms | HTTP/1.1 | nginx |
See the visual redirect chain in the HTTP Probe tab →
Each redirect adds latency. Try to minimize the chain to 1 hop.
Redirect chain — each hop adds latency; combine into one redirect where possible.
Source: Google Search Central / web.dev
If permanent, use 301 instead.
302 (Found) is for genuinely temporary redirects — if this redirect is permanent, switch to 301 to preserve SEO equity.
Learn more ▾ ▴
Search engines treat 302 as temporary, keeping the original URL indexed and not transferring full link equity to the destination. Use 301 (Moved Permanently) for permanent redirects (HTTP→HTTPS, www-vs-non-www, URL restructures).
Source: Google Search Central
DCDN & DeliveryActionNo CDN detectedFIX
Consider using a CDN to improve global delivery speed and reduce origin load.
CIPv6 ReadinessActionNo IPv6 supportREVIEW
IPv6 support is increasingly important for global accessibility. About 40% of internet users have IPv6 connectivity.
No AAAA records — same impact as 'no IPv6 (AAAA) records'; IPv6-preferring clients pay extra latency falling back to IPv4.
Source: Google IPv6 stats
BCrawlabilityrobots.txt present, no sitemapREVIEW
A sitemap helps search engines discover and index your pages more efficiently.
No sitemap.xml — Google relies on crawl-graph discovery alone, slowing indexing of deep or fresh URLs.
Learn more ▾ ▴
A sitemap accelerates Google's discovery of new and updated content. Most CMSes auto-generate one; static-site frameworks need a build-step plugin. Reference it from robots.txt and submit in Search Console to confirm Google can fetch it.
Source: sitemaps.org / Google Search Central
Add a 'Sitemap:' directive to robots.txt so search engines can discover your sitemap.
robots.txt omits Sitemap: directive — crawlers must fetch /sitemap.xml by convention; reliable but missing the explicit hint.
Source: sitemaps.org
User-Agent: *
Disallow: /en/search/
Allow: /
No sitemap found
Adding a sitemap helps search engines discover your pages.
BTLS Certificate Expiry & Recommendations318 days until leaf cert expires — 2 issues to addressREVIEW
Certificate validity
Recommended actions
- Enable HSTS: Strict-Transport-Security: max-age=31536000; includeSubDomains
- Enable OCSP stapling on your TLS server to remove a CA roundtrip and protect user privacy
A+DNS Records1 A records, 157 ms lookupPASS
| A | 192.16.191.43 |
| AAAA | — |
| CNAME | — |
| NS | ns1.cwi.nl, ns1.zurich.surf.net, ns2.cwi.nl, dwalin.nikhef.nl |
| MX | 10 mx.soverin.net |
| TXT | MS=ms63043750 HARICA-SnDN4Irx82qOUXNni8S Centrum Wiskunde & Informatica ZOOM_verify_-TwabqfPQI2RrsWzDjTwfQ ZOOM_verify_QtFtKLPNUTBlqUfH6kXTNZ apple-domain-verification=vKvt2VfbB2WZUhzQ Science Park 123, 1098 XG Amsterdam, Netherlands CWI (Centrum Wiskunde & Informatica)=pnqgTeOiurzbz4yD adobe-idp-site-verification=a8667c98581a66df82f18dd9b4ec9ad04d2b0214fda298afa04b... SPF v=spf1 ip4:192.16.191.0/27 ip4:192.174.88.179 ip4:192.174.88.180 ip4:13.58.74.17... |
| CAA | Lookup not available with standard resolver |
Multiple A records provide failover if one server goes down.
Single A record means a single point of failure — if that IP goes down, your site is unreachable until DNS TTL expires.
Learn more ▾ ▴
Add multiple A records for round-robin failover, or use a managed DNS provider with health-checked failover (Route 53, Cloudflare, NS1). Short TTL (60-300s) lets clients recover faster on outages.
Source: SRE practice / DNS architecture
CAA record lookup requires a specialized DNS resolver. This check will be available in a future update.
Informational: CAA (Certification Authority Authorization) records weren't checked in this scan.
A+URL Variantswww/non-www, trailing slash, HTTP→HTTPSPASS
www / non-www
Preferred variant: non-www
HTTP → HTTPS
Consistent
A+Domain Intelligencecwi.nl — via SURF B.V., 40 years, 6 months old, hosted on CWI-, NLPASS
Unknown
318 days
Issued by Hellenic Academic and Research Institutions CA
40 years, 6 months
Registered April 30, 1986
Enabled
Protects against DNS spoofing
CWI-, NL
ASN AS1888
192.16.191.43
SURF B.V.
Expiry timeline
Recommended actions
- Enable registrar lock (clientTransferProhibited) to block unauthorized domain transfers
The domain can be transferred without an unlock step. Enable registrar lock (clientTransferProhibited) in your registrar's control panel to protect against unauthorized or accidental transfers.
Without registrar lock, an attacker who phishes your registrar credentials can transfer the domain in minutes — total brand hijack.
Learn more ▾ ▴
Registrar lock (clientTransferProhibited, clientUpdateProhibited, clientDeleteProhibited) requires extra verification before any transfer/update/delete. Every major registrar offers it free. Combined with 2FA on your registrar account, it's the strongest defense against domain hijacking.
Source: ICANN / domain-security best practice