llms.txt
+25 −41
https://isitdns.net/llms.txt
− # isitdns.net− > Is it DNS? When a site or domain isn't working, one call audits it: whether the name resolves and why, with a receipt for every reading. Free, no key. isitdns: live health of the public DNS resolvers (Cloudflare 1.1.1.1, Google 8.8.8.8, Quad9, AdGuard and 13 more), a full DNS audit for any domain, a browser dig tool, and a DNS wiki. Independent, free, cookieless. The resolver report reads every probe, each under its name (the probes are listed at /api/vantages); the per-resolver cards read the− Home page HTML: verdict word + failure note · row per resolver (ok/slow/partial/bad/no data) · column per probe · legs (family x transport: latency, RCODE, TIMEOUT) · no data: stale reading or nothing resolved.− ## Live status− - [Is DNS down right now?](https://isitdns.net/): the board's verdict and every public resolver's latest reading.− - [One resolver, in full](https://isitdns.net/api/endpoint?id=cloudflare): JSON for a single resolver. Uptime over 24 hours, 7 days and 30 days, p50 and p95 latency, DNSSEC validation rate, the incident record, and every address on file. Swap the id for google, quad9, adguard or any other on /api/status. Browser view: /#endpoint?id=cloudflare (JS-rendered).− - [How we decide](https://isitdns.net/methodology)− ## Ask without a browser− - Plain text: `curl -sL isitdns.net`− - Over DNS: `dig +short help.isitdns.net TXT` and `dig +short cloudflare.isitdns.net TXT`− - The isitdns protocol (status over DNS: a TXT verdict plus a 127.0.0.2 to .5 address ladder) was designed by Neal Shelton, first published 2026-09-03, and written up as draft-shelton-isitdns-00. Method: https://isitdns.net/methodology− - dig: `curl -sL isitdns.net/dig/<name>/<type>/<resolver>`− - Audit a domain: `curl -sL isitdns.net/check/<domain>`− - Delegation walk: `curl -sL isitdns.net/<domain>`− - JSON: https://isitdns.net/api/status− ## For agents− - MCP: https://isitdns.net/mcp (Streamable HTTP, stateless, no key; protocol 2026-07-28 with server/discover, and the 2025-11-25 to 2024-11-05 revisions through initialize). Tools: check_domain, dig, trace, dnssec_chain, sweep_domain, alias_chain, registration, path_receipt. Add the URL to Claude, ChatGPT, Cursor or any MCP client.− - MCP prompts: diagnose_domain, interception_check, dnssec_check, after_change_check, delegation_check, mail_check, dnssec_servfail, resolver_error_triage, my_network_or_the_domain, check_my_setup, forwarder_chain_walk, is_it_dns. Tool-chained in order, scoped to this name/resolvers/moment; vantage: the isitdns edge or a named probe, never yours.− - Over MCP, dig is DoH from the Cloudflare edge only; the other transports are on /api/query (transport=). Every MCP answer that is not an error ends with two lines: "api: <url>", the /api request behind it, then "ask again: <url>", the page for it (dig, check, trace) or the same /api URL where there is no page (sweep, registration, alias_chain, dnssec_chain, path_receipt); a dig with a non-default flag has no ask again line. Receipts (what was asked, of whom, from where, when, and what came bac− - Refused over MCP, not logged: RFC 6761 special-use (.local .onion .alt .internal) · TLD not in IANA root · RFC 6303 + home.arpa · private ecs prefix− - Official MCP Registry: listed under net.isitdns/isitdns.− - OpenAPI: https://isitdns.net/api/openapi.json− - Live activity: https://isitdns.net/api/activity, every dig, domain check and domain sweep run on the site, newest first, with 24-hour counts. No client IP column.− - One query as a URL: `https://isitdns.net/api/query?name=example.com&type=MX&resolver=quad9` (JSON; with Accept: text/plain the answer is in the shape dig prints). `resolver=all` asks the four tier-1 operators side by side (cloudflare, google, quad9, adguard); any other board resolver is asked by its id. Knobs: transport=doh|dot|tcp53, dnssec=0, cd=1, ecs=, norec=1, nsid=1, family=v4|v6|both, from=north-america|europe (asked over Do53/UDP from that region's probe; the MCP dig and check_domain t− - The same as text: `curl -sL isitdns.net/dig/example.com/MX/quad9`− - GET /api/sweep?domain=&names=&types= (JSON; MCP: sweep_domain) · asks the zone's own servers with RD=0 · CAA + ACME DNS-01 · measured from the edge, theoracle or thewizard · caps 256/sweep, 512/min/caller, 256/min/NS, 2048/min site− - How to read the site: https://isitdns.net/agents− - Every reading: time + vantage (the isitdns edge or a named probe) · rate limit 100/min per address: all MCP calls + HTTP routes hitting a real server− ## Tools− - [dig in the browser](https://isitdns.net/#dig): any name, any type, any public resolver, over DoH, DoT or Do53.− - [Check a domain](https://isitdns.net/#check): delegation, DNSSEC, nameservers, mail posture.− - [Diagnose your DNS in two queries](https://isitdns.net/diagnose): two dig queries from your own terminal that say whether your resolver is the problem.− ## Wiki− - [Wiki index](https://isitdns.net/wiki/): fundamentals, record types, troubleshooting, security, tools.− - [What does SERVFAIL mean](https://isitdns.net/wiki/troubleshooting/servfail)− - [Why dig says connection timed out](https://isitdns.net/wiki/troubleshooting/connection-timed-out)− - [Check a resolver](https://isitdns.net/wiki/troubleshooting/check-a-resolver), [check a delegation](https://isitdns.net/wiki/troubleshooting/check-a-delegation), [check an auth](https://isitdns.net/wiki/troubleshooting/check-an-auth), [check a forwarder](https://isitdns.net/wiki/troubleshooting/check-a-forwarder)− - [dig examples](https://isitdns.net/wiki/tools/dig-examples), [Wireshark DNS filters](https://isitdns.net/wiki/tools/wireshark-dns-filters)− ## Policy− - robots.txt: search and AI answers may read and link; training is refused (Content-Signal: search=yes, ai-input=yes, ai-train=no).+ # isitdns+ > DNS diagnostics. Check a domain, dig a record, walk a delegation, check a DNSSEC chain, compare a zone's servers, read a registration. Over MCP and HTTP; the status also over DNS TXT. No key.+ ## Docs+ - [For agents](https://isitdns.net/agents): connecting a client, reading an answer+ - [Readme](https://isitdns.net/readme): what the board measures+ - [Terms](https://isitdns.net/terms)+ - [Wiki](https://isitdns.net/wiki/)+ ## MCP+ - [Endpoint](https://isitdns.net/mcp): dig is DoH from the edge, or Do53 from a region's probe (from).+ - [check_domain](https://isitdns.net/agents): Check a domain that is not working.+ - [dig](https://isitdns.net/agents): Dig one name and type at one board resolver, or at Cloudflare, Google, Quad9 and AdGuard side by side (resolver all).+ - [trace](https://isitdns.net/agents): Trace a delegation from the root to the authority, like dig +trace.+ - [dnssec_chain](https://isitdns.net/agents): Walk the DNSSEC chain from the root to one answer.+ - [sweep_domain](https://isitdns.net/agents): Sweep a zone's nameservers.+ - [registration](https://isitdns.net/agents): Read a domain's registration from its registry's RDAP server.+ - [Prompts](https://isitdns.net/agents): is_it_dns, after_change_check, mail_check, dnssec_servfail+ ## HTTP+ - [curl -sL isitdns.net](https://isitdns.net/): the board as text+ - [isitdns.net/check/<domain>](https://isitdns.net/check/example.com): the domain check+ - [isitdns.net/dig/<name>/<type>/<resolver>](https://isitdns.net/dig/example.com/A/cloudflare): one record+ - [OpenAPI](https://isitdns.net/api/openapi.json): every /api route+ ## Status+ - [isitdns.net](https://isitdns.net/): the board (17 public resolvers, read from 4 probes)+ - [isit.isitdns.net TXT](https://isitdns.net/readme): the board as TXT+ - [help.isitdns.net TXT](https://isitdns.net/readme): the TXT names