ck12.org
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CK-12 Foundation provides a library of free online textbooks, videos, exercises, flashcards, and real world applications for over 5000 concepts from arithmetic to history
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Updated: 2026-09-24 09:38
Language: English (default)
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Website Overview
An established domain and managed infrastructure suggest continuity of operations and may support dependable delivery, although neither guarantees service quality.
Domain and Registration
Registered in 2006, this domain has about 19 years of history. That suggests continuity, although ownership and purpose may have changed. Transfer-protection status is present, helping reduce the risk of unauthorized domain transfers. The domain uses the common .org extension, which is not an independent safety signal.
DNS and Email
The lowest TTL is 2 seconds, supporting rapid record changes at the cost of more frequent lookups. Nameservers are provided by Amazon Route 53, indicating managed DNS hosting. MX records point to the Google Workspace email service. DNSSEC is enabled, allowing validating resolvers to authenticate signed DNS data. CAA records restrict which certificate authorities are authorized to issue certificates.
TLS and Certificates
The certificate uses an RSA 2048-bit public key, offering broad client compatibility. The server supplied a complete certificate chain. No organization name is present in the certificate; the available fields are consistent with domain validation. The certificate is valid for about 365 days in total, with 70 days remaining. The SAN includes a wildcard covering multiple hostnames at the same subdomain level. Shared private keys can increase the impact of a compromise.
HTTP and Browser Security
The Server header exposes the software version: Apache/2.4.58 (Ubuntu). This makes version-targeted checks easier, but is not proof of an exploitable vulnerability. The response lacks these common security headers: Permissions-Policy. No X-Powered-By header was found, reducing one common source of backend fingerprinting information. The x-cache, via response header indicates a CDN or caching proxy in the delivery path. No obvious internal addresses or debug information were found in the headers.
Technology Stack Analysis
The public page identifies Amazon CloudFront without precise versions, leaving fewer clues for version-specific scanning.
Search and Social Sharing
Unknown
Hosting and Email
Amazon Route 53
Hosting
Google Workspace
Location
United States
Pages, Search and Sharing
| Meta description | Not detected |
|---|---|
| Canonical URL | Not detected |
| Language | English (default) |
| Twitter Card | Not detected |
Unknown
robots.txt (opens in a new tab)
HTTP 403
Unknown
Sitemaps
0No sitemaps found
Registration details RDAP / WHOIS
| Registrar | Amazon Registrar, Inc. |
|---|---|
| Registered | 2006-12-16 |
| Expires | 2028-12-16 |
| Domain status | client transfer prohibited |
| Nameservers | ns-1136.awsdns-14.org、ns-161.awsdns-20.com、ns-1687.awsdns-18.co.uk、ns-977.awsdns-58.net |
| DNSSEC | signed |
DNS records
| Type | Name | Value | TTL | Priority |
|---|---|---|---|---|
| A | www.ck12.org | 3.167.112.123 | 2 | — |
| A | www.ck12.org | 3.167.112.37 | 2 | — |
| A | www.ck12.org | 3.167.112.42 | 2 | — |
| A | www.ck12.org | 3.167.112.74 | 2 | — |
| AAAA | www.ck12.org | 2600:9000:27d1:1a00:8:f05f:c540:93a1 | 60 | — |
| AAAA | www.ck12.org | 2600:9000:27d1:4200:8:f05f:c540:93a1 | 60 | — |
| AAAA | www.ck12.org | 2600:9000:27d1:9600:8:f05f:c540:93a1 | 60 | — |
| AAAA | www.ck12.org | 2600:9000:27d1:ae00:8:f05f:c540:93a1 | 60 | — |
| AAAA | www.ck12.org | 2600:9000:27d1:b400:8:f05f:c540:93a1 | 60 | — |
| AAAA | www.ck12.org | 2600:9000:27d1:be00:8:f05f:c540:93a1 | 60 | — |
| AAAA | www.ck12.org | 2600:9000:27d1:c000:8:f05f:c540:93a1 | 60 | — |
| AAAA | www.ck12.org | 2600:9000:27d1:f800:8:f05f:c540:93a1 | 60 | — |
| MX | ck12.org | aspmx.l.google.com | 120 | 10 |
| MX | ck12.org | alt1.aspmx.l.google.com | 120 | 30 |
| MX | ck12.org | alt2.aspmx.l.google.com | 120 | 30 |
| MX | ck12.org | aspmx2.aspmx.l.google.com | 120 | 50 |
| MX | ck12.org | aspmx4.aspmx.l.google.com | 120 | 50 |
| MX | ck12.org | aspmx5.aspmx.l.google.com | 120 | 50 |
| MX | ck12.org | mail.ck12.org | 120 | 50 |
| NS | ck12.org | ns-1136.awsdns-14.org | 172800 | — |
| NS | ck12.org | ns-161.awsdns-20.com | 172800 | — |
| NS | ck12.org | ns-1687.awsdns-18.co.uk | 172800 | — |
| NS | ck12.org | ns-977.awsdns-58.net | 172800 | — |
| TXT | ck12.org | 5dju5ttjauifkg3ntug8uvdp5o | 120 | — |
| TXT | ck12.org | MS=83D3333E19A93E86CB7555359D6048EE1B9BCFEA | 120 | — |
| TXT | ck12.org | MS=ms18161979 | 120 | — |
| TXT | ck12.org | apple-domain-verification=QF7bv1DM6D2BfMs3 | 120 | — |
| TXT | ck12.org | cursor-domain-verification-ew622e=uyKh14stiqt17t91aYjIpgM0E | 120 | — |
| TXT | ck12.org | facebook-domain-verification=2f23smij2mb05apqoaktiu7od6tn98 | 120 | — |
| TXT | ck12.org | google-site-verification=5I-w_GO6CfZA1FDARhrWTvsloNHQJnWB3WpzO96Q5mI | 120 | — |
| TXT | ck12.org | google-site-verification=E3NQxLaOaxNDjKuRkg4JntlxjO0OkaV7R1i0iMIVMMI | 120 | — |
| TXT | ck12.org | openai-domain-verification=dv-9DfgnOGcp8UMZOccoCfU0yya | 120 | — |
| TXT | ck12.org | v=spf1 ip4:174.129.252.43 ip4:63.236.100.0/24 ip4:66.77.16.0/24 include:emsd1.com include:amazonses.com include:_spf.google.com include:mail.zendesk.com -all | 120 | — |
| CAA | ck12.org | 0 issuewild "amazon.com" | 300 | — |
| CAA | ck12.org | 0 issuewild "godaddy.com" | 300 | — |
| DS | ck12.org | 44845 13 2 ff697df190da79feffdbf2b53a9a6a0c6ef7dc65c549d585302ff914858f8465 | 3600 | — |
| DMARC | _dmarc.ck12.org | v=DMARC1; p=reject; pct=100; rua=mailto:[email protected]; ruf=mailto:[email protected]; adkim=s; aspf=s | 60 | — |
TLS and certificates
| Assessment | Normal configuration |
|---|---|
| Supported protocols | TLSv1.2、TLSv1.3 |
| Negotiated protocol | TLSv1.3 |
| Certificate subject | *.ck12.org |
| Issuer | GoDaddy.com, Inc. |
| Valid until | 2026-12-03T22:34 · Remaining when checked: 70 days |
| Verification details | Certificate trust: Passed · Hostname match: Passed |
HTTP response headers
| Header | Value |
|---|---|
| content-type | text/html; charset=utf-8 |
| server | Apache/2.4.58 (Ubuntu) |
| strict-transport-security | max-age=31536000; includeSubDomains; preload |
| content-security-policy | frame-ancestors 'self' https://*.ck12.org chrome-extension://necpjbiijgficbgfanibojgkcbbooicg; report-uri https://csp-report.ck12.org; report-to ck12-csp-endpoint; |
| x-content-type-options | nosniff |
| referrer-policy | strict-origin-when-cross-origin |
| set-cookie | Redacted |
Identified technologies
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