Skip to content
https://caltech.edu

Infrastructure

· 9 checks — DNS, redirects, IPv6, crawlability, URL variants, and domain intelligence rolled into one auditable list.
SCORE
82
GRADE
B
FIX
2
REVIEW
2
PASS
5
INFO
0
Probed from New York, United Stated
301 Moved Permanently
Checks
9
5 PASS 2 REVIEW 2 FIX
D
URL Variants
Action
www/non-www, trailing slash, HTTP→HTTPS
FIX
www/non-www, trailing slash, HTTP→HTTPS
Critical::
Both www and non-www versions serve content
Got: Both variants return 200 Expected: One variant 301-redirects to the other
Critical::
HTTP version does not redirect to HTTPS
Got: HTTP 301 Expected: 301 redirect to HTTPS

www / non-www

200https://www.caltech.edu/
200https://caltech.edu/

Inconsistent — duplicate content risk

HTTP → HTTPS

301http://caltech.edu/ → http://www.caltech.edu/

HTTP version does not redirect to HTTPS

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.

C
IPv6 Readiness
Action
No IPv6 support
REVIEW
No IPv6 support
Info::
No IPv6 (AAAA) records found
IPv6 support is increasingly important for global accessibility. About 40% of internet users have IPv6 connectivity.
No IPv6 Support
About 40% of internet users have IPv6. Consider adding AAAA records.

IPv6 support is increasingly important for global accessibility. About 40% of internet users have IPv6 connectivity.

Why this matters

No AAAA records — same impact as 'no IPv6 (AAAA) records'; IPv6-preferring clients pay extra latency falling back to IPv4.

Source: Google IPv6 stats

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

Certificate validity

233
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, 5 ms lookup
PASS
1 A records, 5 ms lookup
Info::
Resolves to 1 IPv4 address(es)
Got: 52.26.125.194
Info::
Single A record — no DNS redundancy
Multiple A records provide failover if one server goes down.
Info::
No IPv6 (AAAA) records
Info::
2 nameserver(s) configured
Got: ns0090.secondary.cloudflare.com, ns0239.secondary.cloudflare.com
Info::
2 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
A52.26.125.194
AAAA—
CNAME—
NSns0090.secondary.cloudflare.com, ns0239.secondary.cloudflare.com
MX
10 mx2.caltech.iphmx.com
10 mx1.caltech.iphmx.com
TXT
MS=ms43712753
iContact1389932
ZOOM_verify_a-Gb5-aqQgygEiKsnho63w
apple-domain-verification=KD7b3wNXe76BHRAV
autodesk-domain-verification=TtWEzwdFn86i9o8NX_8R
1password-site-verification=VRLN67QMNNEPXIIREL6TDZABF4
amazonses:CBaUu/J2wBFtHuO9isUzHAXTnIWcN5RyPUBvggu7SNE=
amazonses:X9y0RbFXXvxu3ft83xg2e+YV++OUePTUSeCOdB3Chjg=
anthropic-domain-verification-rw8528=rFwrZAPawzCVNGD318e9zzavQ
Y84qDmmAIPozyUoBIRWmXsFltoU2Pl8b8WGKPlqgz+1t5Db4z9H5ngaaCTq3TTaOK+SCPYUsGVlGn0wU...
adobe-idp-site-verification=1e150df049a820e49156727d1b84c48a1ae11f66f87ad76d2cf3...
SPF v=spf1 ip4:131.215.0.0/16 ip4:134.4.0.0/16 ip4:192.100.16.0/24 ip4:198.129.208.0...
CAALookup not available with standard resolver
Resolved in 5 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), 283 ms total
PASS
1 redirect(s), 283 ms total
Info::
Single redirect
Got: https://caltech.edu → https://www.caltech.edu/ (301)
Info::
WWW normalization redirect

https://caltech.edu

228 ms · HTTP/1.1

301

https://www.caltech.edu/

56 ms · HTTP/1.1 FINAL

#URLStatusTimeProtocolServer
1https://caltech.edu301228 msHTTP/1.1Apache/2.4.37 (Red Hat Enterprise Linux) OpenSSL/1.1.1k
2https://www.caltech.edu/20056 msHTTP/1.1cloudflare

See the visual redirect chain in the HTTP Probe tab →

A+
Crawlability
robots.txt present, sitemap with 64 URLs
PASS
robots.txt present, sitemap with 64 URLs
Info::
robots.txt is present
Got: 265 bytes
Info::
sitemap.xml is present
Info::
sitemap.xml is valid XML
Info::
sitemap.xml contains 64 entries
Info::
robots.txt references sitemap
robots.txt 200 OK
Size 265 B Sitemaps referenced 1 User-agents SemrushBot, BLP_bbot, * Blocking No — crawling allowed
User-agent: SemrushBot
Disallow: /

User-agent: BLP_bbot
Disallow: /

User-agent: *
Disallow: /campus-life-events/calendar/minicalendar/*
Disallow: /map/landmark_ajax/*
Disallow: /map/milestone/*
Crawl-delay: 10
Allow: *
Sitemap: https://www.caltech.edu/sitemap.xml
sitemap.xml 200 OK
Type URL Set URLs 64 entries Valid XML Yes
Sample URLs:
A+
Domain Intelligence
caltech.edu — 40 years, 10 months old, hosted on AWS
PASS
caltech.edu — 40 years, 10 months old, hosted on AWS
Info::
Domain registered until Jul 31, 2027 (1 years, 3 months remaining)
Info::
Hosting: AWS
Got: AS16509
Domain expiry

410 days

July 31, 2027

SSL certificate

233 days

Issued by Internet2

Domain age

40 years, 10 months

Registered January 6, 1986

DNSSEC

Status unknown

Protects against DNS spoofing

Hosting

AWS

ASN AS16509

52.26.125.194

Registrar

Registrar unknown

Lock status unknown 2 NS records
Expiry timeline
Today
+1 year
Domain expiry SSL expiry Danger zone (≤30 days)
Registrar
Created January 6, 1986 (40 years, 10 months ago)
Expires July 31, 2027 (1 years, 3 months)
Last Updated January 30, 2026
Name Servers ns0090.secondary.cloudflare.com, ns0239.secondary.cloudflare.com
Registrant California Institute of Technology
Hosting
IP Address 52.26.125.194
ASN AS16509 (AMAZON-02 - Amazon.com, Inc., US)
Provider AWS
Data source: whois (0.3s)
A+
HTTP Probe Timing
Total 188 ms — DNS, TCP, TLS, TTFB, content transfer breakdown
PASS
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.
60 ms
TLS Handshake TLS Handshake — time to complete the HTTPS encryption handshake.
63 ms
Time to First Byte Time to First Byte — how long the server takes to respond with the first byte of data.
189 ms
Total Time Total request time from DNS lookup through full response.
189 ms

Connection waterfall

DNS Lookup 5 ms TCP Connect 60 ms TLS Handshake 63 ms Server Processing 60 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.

Send Feedback