A curated index of the reference material we use and recommend: the specifications behind the tools, the operational guides worth reading in full, and the external services that do a job better than we do. It exists because finding the authoritative source for a protocol question is often harder than answering the question once you have it.

Entries are annotated with why each resource is worth your time and what it is weak at, which is more useful than a bare list of links.

What is collected

Primary specifications
The RFCs and standards the tools implement, linked to the specific section that governs the behaviour rather than to the document root.
Operational references
Guides for DNS, TLS, mail authentication and web performance that hold up in production.
Complementary tooling
External services that cover ground we deliberately do not.

Frequently asked questions

How are resources selected?

By use. Everything listed is something the team has relied on, and entries that turn out to be stale or superseded are removed rather than left to accumulate.

Can I suggest a resource?

Yes, through the contact page. Suggestions are assessed on whether they are authoritative and current, not on whether they link back.