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https://www.yale.edu

Infrastructure

· 9 checks — DNS, redirects, IPv6, crawlability, URL variants, and domain intelligence rolled into one auditable list.
SCORE
93
GRADE
A
FIX
0
REVIEW
3
PASS
6
INFO
0
Probed from Amsterdam, Netherlands
200 OK
Checks
9
6 PASS 3 REVIEW
B
DNS Records
4 A records, 95 ms lookup
REVIEW
4 A records, 95 ms lookup
Info::
Resolves to 4 IPv4 address(es)
Got: 151.101.2.133, 151.101.66.133, 151.101.130.133, 151.101.194.133
Info::
Has 4 IPv6 (AAAA) record(s)
Got: 2a04:4e42::645, 2a04:4e42:200::645, 2a04:4e42:400::645, 2a04:4e42:600::645
Warning::
CNAME record at zone apex
A CNAME at the zone apex can break MX and NS records. Use ALIAS/ANAME or A records instead.
Got: pantheon-systems.map.fastly.net
Info::
No NS records found
Info::
No MX records — email not configured via DNS
Info::
CAA records not checked
CAA record lookup requires a specialized DNS resolver. This check will be available in a future update.
Info::
No SPF record found in TXT records
SPF helps prevent email spoofing. Add a TXT record starting with 'v=spf1'.
Info::
DNS resolution time: 95 ms
Got: 95 ms
A151.101.2.133, 151.101.66.133, 151.101.130.133, 151.101.194.133
AAAA2a04:4e42::645, 2a04:4e42:200::645, 2a04:4e42:400::645, 2a04:4e42:600::645
CNAMEpantheon-systems.map.fastly.net
NS
MX
TXT
CAALookup not available with standard resolver
Resolved in 95 ms

A CNAME at the zone apex can break MX and NS records. Use ALIAS/ANAME or A records instead.

Why this matters

CNAME at the apex (example.com) breaks every other apex record (MX, TXT, NS) — DNS-protocol violation per RFC 1034.

Learn more

RFC 1034 forbids CNAME alongside other records at the same name. Some DNS providers offer ALIAS / ANAME / flattened-CNAME records that work around this — use those instead. Otherwise apex-level CNAME breaks email (no MX), domain ownership verification (no TXT), and more.

Source: RFC 1034

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.

SPF helps prevent email spoofing. Add a TXT record starting with 'v=spf1'.

Why this matters

Without SPF, receiving servers can't validate sending IPs — your domain is easier to spoof in phishing.

Learn more

SPF complements DMARC. Both should be published. SPF records list authorized sending IPs (e.g., `v=spf1 include:_spf.google.com ~all` for Google Workspace). After publishing, verify in Google Postmaster Tools or mxtoolbox.

Source: RFC 7208 (SPF)

B
Crawlability
robots.txt present, no sitemap
REVIEW
robots.txt present, no sitemap
Info::
robots.txt is present
Got: 2491 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 2491 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: *
Crawl-delay: 10
# CSS, JS, Images
Allow: /misc/*.css$
Allow: /misc/*.css?
Allow: /misc/*.js$
Allow: /misc/*.js?
Allow: /misc/*.gif
Allow: /misc/*.jpg
Allow: /misc/*.jpeg
Allow: /misc/*.png
Allow: /modules/*.css$
Allow: /modules/*.css?
Allow: /modules/*.js$
Allow: /modules/*.js?
Allow: /modules/*.gif
Allow: /modules/*.jpg
Allow: /modules/*.jpeg
Allow: /modules/*.png
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: /themes/*.css$
Allow: /themes/*.css?
Allow: /themes/*.js$
Allow: /themes/*.js?
Allow: /themes/*.gif
Allow: /themes/*.jpg
Allow: /themes/*.jpeg
Allow: /themes/*.png
# Directories
Disallow: /includes/
Disallow: /misc/
Disallow: /modules/
Disallow: /profiles/
Disallow: /scripts/
Disallow: /themes/
# Files
Disallow: /CHANGELOG.txt
Disallow: /cron.php
Disallow: /INSTALL.mysql.txt
Disallow: /INSTALL.pgsql.txt
Disallow: /INSTALL.sqlite.txt
Disallow: /install.php
Disallow: /INSTALL.txt
Disallow: /LICENSE.txt
Disallow: /MAINTAINERS.txt
Disallow: /update.php
Disallow: /UPGRADE.txt
Disallow: /xmlrpc.php
# 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/
# Paths (no clean URLs)
Disallow: /?q=admin/
Disallow: /?q=comment/reply/
Disallow: /?q=filter/tips/
Disallow: /?q=node/add/
Disallow: /?q=search/
Disallow: /?q=user/password/
Disallow: /?q=user/register/
Disallow: /?q=user/login/
Disallow: /?q=user/logout/

# Biblio module rules to prevent recursive searches by bots.
Disallow: /biblio/export/
Disallow: /biblio?*
Disallow: /biblio?page=*&*
Disallow: /publications/export/
Disallow: /publications?*
Disallow: /publications?page=*&*
Disallow: /user/*/biblio*
Allow: /biblio?page=*
Allow: /publications?page=*

sitemap.xml No sitemap found

No sitemap found

Adding a sitemap helps search engines discover your pages.

C
TLS Certificate Expiry & Recommendations
Action
28 days until leaf cert expires — 6 issues to address
REVIEW

Certificate validity

28
days left
0d 30d 60d 90d+
Renew soon — under 30 days remaining

Recommended actions

  • Renew certificate — 28 days remaining
  • Prefer TLS 1.3 — TLS 1.2 is acceptable but TLS 1.3 removes RSA key exchange and improves latency
  • Add includeSubDomains to the HSTS directive
  • Add the preload directive and submit to hstspreload.org once max-age + includeSubDomains are in place
  • 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+
Redirect Chain
No redirects — direct access
PASS
No redirects — direct access
Info::
No redirects — direct access
Got: https://www.yale.edu

https://www.yale.edu

107 ms · HTTP/1.1 FINAL

#URLStatusTimeProtocolServer
1https://www.yale.edu200107 msHTTP/1.1nginx
A+
IPv6 Readiness
IPv6 reachable (1 ms)
PASS
IPv6 reachable (1 ms)
Info::
IPv6 is configured and reachable at 2a04:4e42::645, 2a04:4e42:200::645, 2a04:4e42:400::645, 2a04:4e42:600::645
Got: 1 ms connect
IPv6 Ready
AAAA Records 2a04:4e42::645, 2a04:4e42:200::645, 2a04:4e42:400::645, 2a04:4e42:600::645 Connection Reachable (1 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: www)
Info::
HTTP correctly 301-redirects to HTTPS

www / non-www

200https://www.yale.edu/
301https://yale.edu/

Preferred variant: www

HTTP → HTTPS

301http://www.yale.edu/ https://www.yale.edu/

Consistent

A+
Domain Intelligence
yale.edu — 39 years, 7 months old
PASS
yale.edu — 39 years, 7 months old
Info::
Domain registered until Jul 31, 2027 (1 years, 3 months remaining)
Domain expiry

384 days

July 31, 2027

SSL certificate

28 days

Issued by Certainly

Domain age

39 years, 7 months

Registered March 17, 1987

DNSSEC

Status unknown

Protects against DNS spoofing

Hosting

Unknown

2a04:4e42:600::645

Registrar

Registrar unknown

Lock status unknown 5 NS records
Expiry timeline
Today
+1 year
Domain expiry SSL expiry Danger zone (≤30 days)
Recommended actions
  • Renew the TLS certificate or verify auto-renewal is working
Registrar
Created March 17, 1987 (39 years, 7 months ago)
Expires July 31, 2027 (1 years, 3 months)
Last Updated August 26, 2025
Name Servers ns1.bluecatdns.net, pks1302-103.net.yale.edu, pks1302-102.net.yale.edu, ns1.bluecatdns.com, ns1.bluecatdns.org
Registrant Yale University
Hosting
IP Address 2a04:4e42:600::645
Data source: whois (0.6s)
A+
HTTP Probe Timing
Total 150 ms — DNS, TCP, TLS, TTFB, content transfer breakdown
PASS
DNS Lookup DNS Lookup — time to resolve the domain name to an IP address.
87 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.
34 ms
Time to First Byte Time to First Byte — how long the server takes to respond with the first byte of data.
149 ms
Total Time Total request time from DNS lookup through full response.
150 ms

Connection waterfall

DNS Lookup 87 ms TCP Connect 1 ms TLS Handshake 34 ms Server Processing 27 ms Content Transfer 1 ms
A+
CDN & Delivery
Fastly (HIT, HIT, MISS)
PASS
Fastly (HIT, HIT, MISS)
Info::
Site is served via Fastly CDN
Got: x-served-by: cache-chi-kigq8000138-CHI, cache-rtm-ehrd2290040-RTM, cache-rtm-ehrd2290047-RTM
Info::
CDN cache status: HIT, HIT, MISS
CDN Detected: Fastly
Provider Fastly Cache Status HIT, HIT, MISS Evidence x-served-by: cache-chi-kigq8000138-CHI, cache-rtm-ehrd2290040-RTM, cache-rtm-ehrd2290047-RTM
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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