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https://cern.ch

Infrastructure

· 9 checks — DNS, redirects, IPv6, crawlability, URL variants, and domain intelligence rolled into one auditable list.
SCORE
90
GRADE
A
FIX
1
REVIEW
2
PASS
5
INFO
1
Probed from Madrid, Spain
302 Found
Checks
9
5 PASS 2 REVIEW 1 FIX
D
CDN & Delivery
Action
No CDN detected
FIX
No CDN detected
Warning::
No CDN detected
A CDN can significantly improve load times for users around the world by caching content at edge nodes closer to them.
No CDN detected

Consider using a CDN to improve global delivery speed and reduce origin load.

B
Crawlability
no robots.txt, no sitemap
REVIEW
no robots.txt, no sitemap
Info::
No robots.txt found
robots.txt is optional but recommended. It tells search engine crawlers which pages to index.
Info::
No sitemap.xml found
A sitemap helps search engines discover and index your pages more efficiently.

robots.txt is optional but recommended. It tells search engine crawlers which pages to index.

Why this matters

No robots.txt — crawlers fetch /robots.txt and get 404; not breaking but means default crawl behavior with no directives or sitemap reference.

Learn more ▾

A minimal robots.txt with `User-agent: * / Allow: / / Sitemap: https://example.com/sitemap.xml` covers the basics. Without it, crawlers behave fine but lose the sitemap signal and can't be selectively blocked from crawl-traps.

Source: robotstxt.org

A sitemap helps search engines discover and index your pages more efficiently.

Why this matters

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

robots.txt No robots.txt found

No robots.txt found

This is fine for most sites — a missing robots.txt allows all crawling by default.

sitemap.xml No sitemap found

No sitemap found

Adding a sitemap helps search engines discover your pages.

B
TLS Certificate Expiry & Recommendations
217 days until leaf cert expires — 3 issues to address
REVIEW

Certificate validity

217
days left
0d 30d 60d 90d+

Recommended actions

  • Enable HSTS: Strict-Transport-Security: max-age=31536000; includeSubDomains
  • Enable DNSSEC on your domain for DNS spoofing protection
  • Enable OCSP stapling on your TLS server to remove a CA roundtrip and protect user privacy
A+
DNS Records
1 A records, 39 ms lookup
PASS
1 A records, 39 ms lookup
Info::
Resolves to 1 IPv4 address(es)
Got: 188.184.77.250
Info::
Single A record — no DNS redundancy
Multiple A records provide failover if one server goes down.
Info::
Has 1 IPv6 (AAAA) record(s)
Got: 2001:1458:d00:3c::100:2f9
Info::
3 nameserver(s) configured
Got: ext-dns-2.cern.ch, scsnms.switch.ch, ext-dns-1.cern.ch
Info::
1 mail exchanger(s) configured
Info::
CAA records not checked
CAA record lookup requires a specialized DNS resolver. This check will be available in a future update.
Info::
SPF record present in TXT
Info::
DNS resolution time: 39 ms
Got: 39 ms
A188.184.77.250
AAAA2001:1458:d00:3c::100:2f9
CNAME—
NSext-dns-2.cern.ch, scsnms.switch.ch, ext-dns-1.cern.ch
MX
10 cern-ch.mail.protection.outlook.com
TXT
openai-domain-verification=dv-R5PuLWpZKT8QhVzrlbLDHvBz
goqTmP4CYqgXEPONka9g8FCGD4vpvjieG4RI5NLxYZsBh/y5p88K9ym3zIFcLVbaYQdJkdhfYcjADXGd...
google-site-verification=aoFc91q4kA9Xp_-Z_AFY1gI0AmXpTXIMcGseZfvH0J8
mistral-domain-verification=3a255465ec599b8016fb91a2f8563cc304e3b95d
MS=ms44269116
autodesk-domain-verification=5Lt81tqLuEgD4wCC73YQ
SPF v=spf1 include:spf.cern.ch ?all
cursor-domain-verification-8t0p9r=J6wFIABgbtZfHacKasG8HDZ1p
CAALookup not available with standard resolver
Resolved in 39 ms

Multiple A records provide failover if one server goes down.

Why this matters

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.

Why this matters

Informational: CAA (Certification Authority Authorization) records weren't checked in this scan.

A
Redirect Chain
1 redirect(s), 242 ms total
PASS
1 redirect(s), 242 ms total
Info::
Single redirect
Got: https://cern.ch → https://home.cern (302)
Info::
Uses 302 (temporary) redirect
If permanent, use 301 instead.
Got: https://cern.ch
Info::
Cross-domain redirect detected

https://cern.ch

101 ms · HTTP/1.1

302

https://home.cern

141 ms · HTTP/1.1 FINAL

#URLStatusTimeProtocolServer
1https://cern.ch302101 msHTTP/1.1
2https://home.cern200141 msHTTP/1.1nginx

See the visual redirect chain in the HTTP Probe tab →

If permanent, use 301 instead.

Why this matters

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

A+
IPv6 Readiness
IPv6 reachable (31 ms)
PASS
IPv6 reachable (31 ms)
Info::
IPv6 is configured and reachable at 2001:1458:d00:3c::100:2f9
Got: 31 ms connect
IPv6 Ready
AAAA Records 2001:1458:d00:3c::100:2f9 Connection Reachable (31 ms)
A
URL Variants
www/non-www, trailing slash, HTTP→HTTPS
PASS
www/non-www, trailing slash, HTTP→HTTPS
Info::
www/non-www redirect configured correctly (preferred: non-www)
Warning::
HTTP→HTTPS redirect uses 302 instead of 301
Got: 302 temporary redirect Expected: 301 permanent redirect

www / non-www

302https://www.cern.ch/
200https://cern.ch/

Preferred variant: non-www

HTTP → HTTPS

302http://cern.ch/ → https://home.cern

Use 301 (permanent) instead of 302 (temporary)

A+
HTTP Probe Timing
Total 139 ms — DNS, TCP, TLS, TTFB, content transfer breakdown
PASS
DNS Lookup DNS Lookup — time to resolve the domain name to an IP address.
39 ms
TCP Connect TCP Connect — time to establish a TCP connection to the server.
32 ms
TLS Handshake TLS Handshake — time to complete the HTTPS encryption handshake.
36 ms
Time to First Byte Time to First Byte — how long the server takes to respond with the first byte of data.
139 ms
Total Time Total request time from DNS lookup through full response.
139 ms

Connection waterfall

DNS Lookup 39 ms TCP Connect 32 ms TLS Handshake 36 ms Server Processing 33 ms Content Transfer 0 ms
Domain Intelligence
Domain intelligence data not available
INFO
Domain intelligence data not available

RDAP and WHOIS lookup both failed

All checks on this page are automated. Results are estimates - run targeted manual reviews when the score affects a release decision.

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