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Infrastructure

· 9 checks — DNS, redirects, IPv6, crawlability, URL variants, and domain intelligence rolled into one auditable list.
SCORE
95
GRADE
A
FIX
0
REVIEW
3
PASS
6
INFO
0
Probed from Singapore, Singapore
200 OK
Checks
9
6 PASS 3 REVIEW
B
Crawlability
robots.txt present, no sitemap
REVIEW
robots.txt present, no sitemap
Info::
robots.txt is present
Got: 2027 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 2027 B Sitemaps referenced 0 User-agents * Blocking No — crawling allowed
#
# robots.txt
#
# This file is to prevent the crawling and indexing of certain parts
# of your site by web crawlers and spiders run by sites like Yahoo!
# and Google. By telling these "robots" where not to go on your site,
# you save bandwidth and server resources.
#
# This file will be ignored unless it is at the root of your host:
# Used:    http://example.com/robots.txt
# Ignored: http://example.com/site/robots.txt
#
# For more information about the robots.txt standard, see:
# http://www.robotstxt.org/robotstxt.html

User-agent: *
# CSS, JS, Images
Allow: /core/*.css$
Allow: /core/*.css?
Allow: /core/*.js$
Allow: /core/*.js?
Allow: /core/*.gif
Allow: /core/*.jpg
Allow: /core/*.jpeg
Allow: /core/*.png
Allow: /core/*.svg
Allow: /profiles/*.css$
Allow: /profiles/*.css?
Allow: /profiles/*.js$
Allow: /profiles/*.js?
Allow: /profiles/*.gif
Allow: /profiles/*.jpg
Allow: /profiles/*.jpeg
Allow: /profiles/*.png
Allow: /profiles/*.svg
# Directories
Disallow: /core/
Disallow: /profiles/
# Files
Disallow: /README.md
Disallow: /composer/Metapackage/README.txt
Disallow: /composer/Plugin/ProjectMessage/README.md
Disallow: /composer/Plugin/Scaffold/README.md
Disallow: /composer/Plugin/VendorHardening/README.txt
Disallow: /composer/Template/README.txt
Disallow: /modules/README.txt
Disallow: /sites/README.txt
Disallow: /themes/README.txt
Disallow: /web.config
# Paths (clean URLs)
Disallow: /admin/
Disallow: /comment/reply/
Disallow: /filter/tips
Disallow: /node/add/
Disallow: /search/
Disallow: /user/register
Disallow: /user/password
Disallow: /user/login
Disallow: /user/logout
Disallow: /media/oembed
Disallow: /*/media/oembed
# Paths (no clean URLs)
Disallow: /index.php/admin/
Disallow: /index.php/comment/reply/
Disallow: /index.php/filter/tips
Disallow: /index.php/node/add/
Disallow: /index.php/search/
Disallow: /index.php/user/password
Disallow: /index.php/user/register
Disallow: /index.php/user/login
Disallow: /index.php/user/logout
Disallow: /index.php/media/oembed
Disallow: /index.php/*/media/oembed
sitemap.xml No sitemap found

No sitemap found

Adding a sitemap helps search engines discover your pages.

B
HTTP Probe Timing
Total 1235 ms — DNS, TCP, TLS, TTFB, content transfer breakdown
REVIEW
DNS Lookup DNS Lookup — time to resolve the domain name to an IP address.
5 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.
10 ms
Time to First Byte Time to First Byte — how long the server takes to respond with the first byte of data.
763 ms
Total Time Total request time from DNS lookup through full response.
1.24 s

Connection waterfall

DNS Lookup 5 ms TCP Connect 1 ms TLS Handshake 10 ms Server Processing 748 ms Content Transfer 473 ms
B
TLS Certificate Expiry & Recommendations
36 days until leaf cert expires — 3 issues to address
REVIEW

Certificate validity

36
days left
0d 30d 60d 90d+

Recommended actions

  • Add includeSubDomains to the HSTS directive
  • Add the preload directive and submit to hstspreload.org once max-age + includeSubDomains are in place
  • Enable OCSP stapling on your TLS server to remove a CA roundtrip and protect user privacy
A+
DNS Records
2 A records, 5 ms lookup
PASS
2 A records, 5 ms lookup
Info::
Resolves to 2 IPv4 address(es)
Got: 104.20.33.226, 172.66.163.119
Info::
Has 2 IPv6 (AAAA) record(s)
Got: 2606:4700:10::6814:21e2, 2606:4700:10::ac42:a377
Info::
2 nameserver(s) configured
Got: ridge.ns.cloudflare.com, celine.ns.cloudflare.com
Info::
5 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
A104.20.33.226, 172.66.163.119
AAAA2606:4700:10::6814:21e2, 2606:4700:10::ac42:a377
CNAME—
NSridge.ns.cloudflare.com, celine.ns.cloudflare.com
MX
1 aspmx.l.google.com
5 alt1.aspmx.l.google.com
5 alt2.aspmx.l.google.com
10 alt4.aspmx.l.google.com
10 alt3.aspmx.l.google.com
TXT
MS=24EEDA32A1B64093067F80942348F46B7C53AB15
1password-site-verification=YDXLXEOPD5A4RIQ4DGBXTTLXAU
google-site-verification=ej-DagC8sD_MaouJikcyiz-sulM4oKdtg95K_XZJLjc
google-site-verification=zIAad45IZShT-a7Q2GnGn7XjbofS1NobaXCuldPdF58
SPF v=spf1 include:_spf.google.com include:mailgun.org include:spf.mailjet.com ~all
atlassian-domain-verification=K5DMrg/KPVIJcji/XYQ5GaWR5qtDtay27IEufDV87yqJmqX4uK...
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+
Redirect Chain
No redirects — direct access
PASS
No redirects — direct access
Info::
No redirects — direct access
Got: https://libretexts.org

https://libretexts.org

729 ms · HTTP/1.1 FINAL

#URLStatusTimeProtocolServer
1https://libretexts.org200729 msHTTP/1.1cloudflare
A+
IPv6 Readiness
IPv6 reachable (1 ms)
PASS
IPv6 reachable (1 ms)
Info::
IPv6 is configured and reachable at 2606:4700:10::6814:21e2, 2606:4700:10::ac42:a377
Got: 1 ms connect
IPv6 Ready
AAAA Records 2606:4700:10::6814:21e2, 2606:4700:10::ac42:a377 Connection Reachable (1 ms)
A+
URL Variants
www/non-www, trailing slash, HTTP→HTTPS
PASS
www/non-www, trailing slash, HTTP→HTTPS
Info::
HTTP correctly 301-redirects to HTTPS

www / non-www

https://www.libretexts.org/
200https://libretexts.org/

HTTP → HTTPS

301http://libretexts.org/ → https://libretexts.org/

Consistent

A
Domain Intelligence
libretexts.org — via Squarespace Domains II LLC, 9 years, 10 months old
PASS
libretexts.org — via Squarespace Domains II LLC, 9 years, 10 months old
Warning::
Domain expires in 90 days
Consider enabling auto-renewal to prevent accidental expiration.
Got: Expires Jul 22, 2026
Info::
DNSSEC is enabled
Info::
Registrar: Squarespace Domains II LLC
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

37 days

July 22, 2026

SSL certificate

36 days

Issued by Google Trust Services

Domain age

9 years, 10 months

Registered July 22, 2016

DNSSEC

Enabled

Protects against DNS spoofing

Hosting

Unknown

2606:4700:10::6814:21e2

Registrar

Squarespace Domains II LLC

Unlocked 2 NS records
Expiry timeline
Today
+1 year
Domain expiry SSL expiry Danger zone (≤30 days)
Recommended actions
  • Renew the domain or enable auto-renewal to prevent accidental expiry
  • Enable registrar lock (clientTransferProhibited) to block unauthorized domain transfers
Registrar Squarespace Domains II LLC
Created July 22, 2016 (9 years, 10 months ago)
Expires July 22, 2026 (3 months)
Last Updated July 17, 2025
Name Servers celine.ns.cloudflare.com, ridge.ns.cloudflare.com
DNSSEC Enabled
Hosting
IP Address 2606:4700:10::6814:21e2
Data source: rdap (0.2s)

Consider enabling auto-renewal to prevent accidental expiration.

Why this matters

Domain expiry approaching — renew immediately and ensure auto-renew + alerting are configured.

Source: ICANN renewal policy

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
CDN & Delivery
Cloudflare (DYNAMIC)
PASS
Cloudflare (DYNAMIC)
Info::
Site is served via Cloudflare CDN (edge: SIN)
Got: cf-ray: 9f0872bb395c81a2-SIN
Info::
CDN cache status: DYNAMIC
CDN Detected: Cloudflare
Provider Cloudflare Cache Status DYNAMIC Evidence cf-ray: 9f0872bb395c81a2-SIN
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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