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Infrastructure

· 9 checks — DNS, redirects, IPv6, crawlability, URL variants, and domain intelligence rolled into one auditable list.
SCORE
90
GRADE
A
FIX
0
REVIEW
4
PASS
5
INFO
0
Probed from Sao Paulo, Brazil
302 Found
Checks
9
5 PASS 4 REVIEW
B
Redirect Chain
2 redirect(s), 568 ms total
REVIEW
2 redirect(s), 568 ms total
Warning::
2 redirects before reaching final URL
Each redirect adds latency. Try to minimize the chain to 1 hop.
Info::
Uses 302 (temporary) redirect
If permanent, use 301 instead.
Got: https://readthedocs.org
Info::
Redirect overhead: 568 ms total
Got: 568 ms
Info::
Cross-domain redirect detected

https://readthedocs.org

18 ms · HTTP/1.1

302

https://app.readthedocs.org/welcome/

474 ms · HTTP/1.1

302

https://about.readthedocs.com/?ref=app.r...

77 ms · HTTP/1.1 FINAL

#URLStatusTimeProtocolServer
1https://readthedocs.org30218 msHTTP/1.1cloudflare
2https://app.readthedocs.org/welcome/302474 msHTTP/1.1cloudflare
3https://about.readthedocs.com/?ref=app.r...20077 msHTTP/1.1cloudflare

See the visual redirect chain in the HTTP Probe tab →

Each redirect adds latency. Try to minimize the chain to 1 hop.

Why this matters

Redirect chain — each hop adds latency; combine into one redirect where possible.

Source: Google Search Central / web.dev

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

B
Crawlability
robots.txt present, no sitemap
REVIEW
robots.txt present, no sitemap
Info::
robots.txt is present
Got: 192 bytes
Info::
No sitemap.xml found
A sitemap helps search engines discover and index your pages more efficiently.
Info::
robots.txt does not reference a sitemap
Add a 'Sitemap:' directive to robots.txt so search engines can discover your sitemap.

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

Add a 'Sitemap:' directive to robots.txt so search engines can discover your sitemap.

Why this matters

robots.txt omits Sitemap: directive — crawlers must fetch /sitemap.xml by convention; reliable but missing the explicit hint.

Source: sitemaps.org

robots.txt 200 OK
Size 192 B Sitemaps referenced 0 User-agents *, AhrefsBot Blocking No — crawling allowed
User-agent: *
Disallow: /search/
Disallow: /api/
Disallow: /builds/
Disallow: /sustainability/click/

# This was hitting our site and causing a lot of issues
User-agent: AhrefsBot
Disallow: /

sitemap.xml No sitemap found

No sitemap found

Adding a sitemap helps search engines discover your pages.

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

Certificate validity

87
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
B
CDN & Delivery
Cloudflare
REVIEW
Cloudflare
Info::
Site is served via Cloudflare CDN (edge: GRU)
Got: cf-ray: 9eff0627f85e01a6-GRU
CDN Detected: Cloudflare
Provider Cloudflare Evidence cf-ray: 9eff0627f85e01a6-GRU
A+
DNS Records
2 A records, 5 ms lookup
PASS
2 A records, 5 ms lookup
Info::
Resolves to 2 IPv4 address(es)
Got: 104.18.6.29, 104.18.7.29
Info::
Has 2 IPv6 (AAAA) record(s)
Got: 2606:4700::6812:71d, 2606:4700::6812:61d
Info::
2 nameserver(s) configured
Got: ivan.ns.cloudflare.com, tegan.ns.cloudflare.com
Info::
3 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: 5 ms
Got: 5 ms
A104.18.6.29, 104.18.7.29
AAAA2606:4700::6812:71d, 2606:4700::6812:61d
CNAME
NSivan.ns.cloudflare.com, tegan.ns.cloudflare.com
MX
1 aspmx.l.google.com
5 alt1.aspmx.l.google.com
5 alt2.aspmx.l.google.com
TXT
google-site-verification=-GDxsd6bay3wIn9zgT0lG0397PpmQMBKzP_W6B9oSxM
SPF v=spf1 include:_spf.mlsend.com include:_spf.google.com ~all
CAALookup not available with standard resolver
Resolved in 5 ms

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+
IPv6 Readiness
IPv6 reachable (2 ms)
PASS
IPv6 reachable (2 ms)
Info::
IPv6 is configured and reachable at 2606:4700::6812:71d, 2606:4700::6812:61d
Got: 2 ms connect
IPv6 Ready
AAAA Records 2606:4700::6812:71d, 2606:4700::6812:61d Connection Reachable (2 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.readthedocs.org/
200https://readthedocs.org/

Preferred variant: non-www

HTTP → HTTPS

302http://readthedocs.org/ https://app.readthedocs.org/welcome/

Use 301 (permanent) instead of 302 (temporary)

A+
Domain Intelligence
readthedocs.org — via Cloudflare, Inc., 15 years, 11 months old
PASS
readthedocs.org — via Cloudflare, Inc., 15 years, 11 months old
Info::
Domain registered until Aug 12, 2029 (3 years, 4 months remaining)
Info::
DNSSEC is not enabled
DNSSEC protects against DNS spoofing attacks. While not required, enabling DNSSEC adds an additional layer of security. Contact your DNS provider to enable it.
Info::
Registrar: Cloudflare, Inc.
Warning::
Registrar lock is NOT enabled
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.
Domain expiry

1127 days

August 12, 2029

SSL certificate

87 days

Issued by Google Trust Services

Domain age

15 years, 11 months

Registered August 12, 2010

DNSSEC

Not enabled

Protects against DNS spoofing

Hosting

Unknown

2606:4700::6812:61d

Registrar

Cloudflare, Inc.

Unlocked 2 NS records
Expiry timeline
Today
+1 year
Domain expiry SSL expiry Danger zone (≤30 days)
Recommended actions
  • Enable DNSSEC to protect visitors from DNS spoofing
  • Enable registrar lock (clientTransferProhibited) to block unauthorized domain transfers
Registrar Cloudflare, Inc.
Created August 12, 2010 (15 years, 11 months ago)
Expires August 12, 2029 (3 years, 4 months)
Last Updated June 24, 2025
Name Servers ivan.ns.cloudflare.com, tegan.ns.cloudflare.com
DNSSEC Not enabled
Hosting
IP Address 2606:4700::6812:61d
Data source: rdap (1.3s)

DNSSEC protects against DNS spoofing attacks. While not required, enabling DNSSEC adds an additional layer of security. Contact your DNS provider to enable it.

Why this matters

Without DNSSEC, an attacker who can poison your DNS can hijack your domain — and SSL certs alone don't stop them.

Learn more

DNSSEC adds cryptographic signatures to DNS records, preventing forged responses from poisoning resolver caches. Without it, an attacker who controls the network path can redirect your domain to a malicious server before any HTTPS handshake happens. Most modern registrars (Cloudflare, Google Domains, Route 53) enable it with one toggle.

Source: ICANN / RFC 4033

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.

Why this matters

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

A+
HTTP Probe Timing
Total 18 ms — DNS, TCP, TLS, TTFB, content transfer breakdown
PASS
DNS Lookup DNS Lookup — time to resolve the domain name to an IP address.
2 ms
TCP Connect TCP Connect — time to establish a TCP connection to the server.
1 ms
TLS Handshake TLS Handshake — time to complete the HTTPS encryption handshake.
8 ms
Time to First Byte Time to First Byte — how long the server takes to respond with the first byte of data.
18 ms
Total Time Total request time from DNS lookup through full response.
18 ms

Connection waterfall

DNS Lookup 2 ms TCP Connect 1 ms TLS Handshake 8 ms Server Processing 6 ms Content Transfer 0 ms
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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