Knowledge Base

Explore practical guides and answers by topic to understand web technologies and discover useful websites.

Answers and Guides

Understanding RDAP: A standard protocol for looking up a domain's registrar, registration date, expiry date and status.
Understanding DNS: Translates domains into server addresses and carries records for email, verification and security policies.
Understanding DNSSEC: Uses digital signatures to check whether DNS responses have been tampered with.
Understanding MX records: Specify which mail servers should receive email addressed to a domain.
Understanding SPF: Declares which servers are authorized to send email on behalf of a domain.
Understanding DKIM: Uses digital signatures to verify email integrity and the signing domain.
Understanding DMARC: Defines handling and reporting policies for messages that fail aligned email authentication.
Understanding CAA: Restricts which certificate authorities may issue certificates for a domain.
Understanding TLS: Provides encryption, authentication and integrity for connections between browsers and websites.
Understanding SAN: Lists the identities actually covered by a TLS certificate.
Understanding HTTP Response Headers: Response fields describing content, caching, redirects and security policies.
Understanding HSTS: Tells browsers to access a website only through HTTPS for a specified period.
Understanding CSP: Restricts the sources from which a page may load and execute scripts, styles and other resources.
Understanding CORS: Controls whether scripts on other origins may read a resource's response.
Understanding Canonical: Identifies the preferred URL among a group of identical or substantially similar pages.
Understanding Open Graph: Supplies titles, descriptions and images for social link previews.
Understanding Twitter Card: Provides platform-specific metadata for link previews on X/Twitter.
Understanding robots.txt: Tells compliant crawlers which paths they may or may not fetch.
Understanding Sitemap: Lists canonical pages a site wants search engines to discover and crawl.
Understanding Structured Data: Describes page entities, properties and relationships in a machine-readable format.