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Guides
Practical, no-fluff explanations of the network protocols and records you actually have to debug. Each guide pairs with a tool on this site so you can run the lookup yourself.
DNS
DNS Records Explained
A practical guide to A, AAAA, CNAME, MX, TXT, NS, CAA, and other DNS record types.
7 min read · Updated 2026-05-06MX Records And Email Routing
How mail exchanger records decide where domain email is delivered and how to troubleshoot them.
6 min read · Updated 2026-05-06SPF, DKIM, And DMARC Explained
A domain owner's guide to the DNS records that help receivers trust email.
8 min read · Updated 2026-05-06TLS
TLS Certificate Expiration And Troubleshooting
How to inspect certificate dates, names, issuers, and trust problems before users see errors.
7 min read · Updated 2026-05-06