CAA DNS records: the complete guide to controlling who issues your certificates
Everything about the CAA DNS record: syntax, issue/issuewild/iodef tags, critical flag, inheritance, RFC 8659 and 8657, multi-provider setup, and auditing.
CaptainDNS Blog
DNS, email authentication, AI integrations and product updates.
Technical guides, comparisons and insights on public DNS resolvers (Cloudflare, Google, Quad9), email authentication (SPF, DKIM, DMARC, BIMI, ARC) and deliverability. Learn how to configure Amazon SES, Brevo, SendGrid or Mailjet, and explore our AI integrations with ChatGPT and the MCP protocol. Whether you're a sysadmin, developer or marketing manager, find best practices here to secure your domains and optimize your email delivery.
Articles
June 2026
ARC moves to "Historic" status at the IETF: should you still care in 2026?
The IETF is reclassifying ARC (RFC 8617) as "Historic." But deprecated on paper does not mean dead in practice: Apple, Google and Microsoft still require it. Here is what really changes and what you should do.
May 2026
Email deliverability score: what it's made of and how to improve it
The email deliverability score is not a black box. It rests on five measurable pillars: authentication, reputation, transport security, BIMI and engagement. This guide breaks them down and gives the thresholds to aim for.
DORA, NIS2 and status pages: turning incident communication into EU compliance evidence
In 2026, the status page is no longer a marketing tool. It is an admissible audit artifact for DORA, NIS2 and GDPR. A complete operational guide.
HTTP redirects and AI crawlers in 2026: what GPTBot, ClaudeBot and PerplexityBot really see on your site
GPTBot, ClaudeBot and PerplexityBot do not follow redirects like Googlebot. Understand their actual behavior to stay visible in ChatGPT, Claude and Perplexity.
Phishing vs spear phishing: what's the difference in 2026?
Phishing targets the masses, spear phishing targets the person. In 2026, AI, OSINT, and deepfakes blur the line. Full breakdown with real cases and defenses.
April 2026
HSTS: the complete guide to enable Strict-Transport-Security and the preload list
HSTS (RFC 6797) forces browsers to contact your site only over HTTPS. This guide covers the protocol, the directives, per-stack configurations and how to submit to the Chrome preload list.