Registered 32 years ago, on no blocklists we checked, valid HTTPS, the site answered 200 in 84 ms.
Rule-based: domain age, blocklists, TLS. A heuristic, not a guarantee.

| A | 104.16.45.99 104.16.44.99 |
|---|---|
| AAAA | 2606:4700::6810:2d63 2606:4700::6810:2c63 |
| MX | 0 mx.ietf.org |
| NS | ken.ns.cloudflare.com jill.ns.cloudflare.com |
| TXT | vs58md9pf8hu6knlglfda9lk6g ca3-5567e36d3f9947308ac2892e009840cc google-site-verification=NQpGlv9isd8O_RHzO31C0lOw1XKfQfFoVhZbmir6Lm4 v=spf1 ip4:166.84.6.31 ip4:166.84.7.238 ip6:2602:f977:800:f7f6::/64 ip4:166.84.7.34 ip6:2602:f977:800::e276:63ff:fe66:3400 include:_spf.google.com include:spf.hostedrt.com ~all google-site-verification=mvpHmuqmM4wrWv5w3S1AAqssmhAITNo2QqPqVLrVWEo |
| registrar | Cloudflare, Inc. |
|---|---|
| registered | 1995-03-11 |
| expires | 2031-03-12 |
| last changed | 2026-08-12 |
| owner | DATA REDACTED |
| nameservers | jill.ns.cloudflare.com ken.ns.cloudflare.com |
| status | server delete prohibited client transfer prohibited |
| valid | yes |
|---|---|
| issuer | Google Trust Services |
| covers | ietf.org, trustee.ietf.org, *.trustee.ietf.org |
| protocol | TLSv1.3 |
Domain is properly signed — chain validated by an independent validating resolver
| SPF | pass v=spf1 ip4:166.84.6.31 ip4:166.84.7.238 ip6:2602:f977:800:f7f6::/64 ip4:166.84.7.34 ip6:2602:f977:800::e276:63ff:fe66:3400 include:_spf.google.com include:spf.hostedrt.com ~all |
|---|---|
| DMARC | warning policy none |
| DKIM | found: mail |
Whether mail claiming to be from this domain can be checked as genuine.
Green: clean. Red: listed. Grey: the list did not answer.
Agents get this as data. Bought through the API, the checks behind this page cost $0.070: profile $0.025 + trust $0.020 + screenshot $0.020 + site status $0.005.
MCP: add https://how.is/mcp to Claude, Codex or Cursor
(one-line install) and ask for domain_trust on ietf.org.
Reference: /llms.txt.
Watch ietf.org. DNS read at the source every 5 minutes; certificate, blocklists and expiry every 6 hours. You get an email only when something changes.
Watch — $1 / 30 days