indexo.dev

cut-the-knot.org

.org crawl

First seen 2026-04-15 · Last seen 2026-05-10 · ok HTTP/1.1 200 1604 ms crawled 2026-05-10

US · 107.180.50.227 · AS400754 GoDaddy.com, LLC

Reputation 95/100 weak security headers

Classifying

HTML metadata

Title
Interactive Mathematics Miscellany <br>and Puzzles
Description
An encyclopedic collection of math resources for all grades. Arithmetic games, problems, puzzles, and articles

Technology

Server
Apache

Third-party hosts loaded (2)

  • code.jquery.com×1
  • www.wolframcdn.com×1

Social

Registration

Registrar
GoDaddy Corporate Domains, LLC
Created
2001-11-06
Expires
2026-11-06 169 days left
Updated
2025-03-17
Name servers
  • ns10.gcd-dns.com
  • ns09.gcd-dns.com

DNS records live

NS
  • ns09.gcd-dns.com
  • ns10.gcd-dns.com

Email authentication no MX

SPF
not published
DMARC
not published
DKIM
no key found at common selectors

Certificate (current)

Go Daddy Secure Certificate Authority - G2
from 2025-10-12 to 2026-11-13
Expires in 176 days

Full certificate history on crt.sh ↗

HTTP security headers

Header hygiene 30/100 Checked live page: https://cut-the-knot.org/

findings
  • missing HSTS
  • missing Content Security Policy
  • missing frame protection
  • missing content type protection
  • missing Referrer Policy
  • missing Permissions Policy

Links to (4)

Linked from (2)