{"kind":"host","input":"sso.oreilly.com","report":{"host":"sso.oreilly.com","checkedAt":"2026-11-01T16:40:39.769Z","a":{"status":"found","values":["104.18.34.7","172.64.153.249"],"ttl":60,"via":"Cloudflare","cname":["learning-cd-vdue44vdsl9llt0m.edge.tenants.oreilly.auth0app.com","learning.oreilly.auth0app.com","plwpo8.oreilly.auth0app.com.pivot.prod.auth0edge.com","ingress.oreilly.auth0app.com.cdn.cloudflare.net"]},"aaaa":{"status":"found","values":["2606:4700:440b::ac40:99f9","2a06:98c1:3101::6812:2207"],"ttl":60,"via":"Cloudflare","cname":["learning-cd-vdue44vdsl9llt0m.edge.tenants.oreilly.auth0app.com","learning.oreilly.auth0app.com","plwpo8.oreilly.auth0app.com.pivot.prod.auth0edge.com","ingress.oreilly.auth0app.com.cdn.cloudflare.net"]},"verdict":"dual-stack"},"readiness":{"grade":"A","summary":"Website, mail and DNS all work over IPv6.","reachabilityTested":true,"checks":[{"key":"web","label":"Website over IPv6","status":"pass","detail":"sso.oreilly.com has 2 IPv6 addresses and answers on every one we tested.","addresses":[{"address":"2606:4700:440b::ac40:99f9","result":"answers","port":443},{"address":"2a06:98c1:3101::6812:2207","result":"answers","port":443}]},{"key":"mail","label":"Mail servers (MX) have IPv6","status":"pass","detail":"No MX records, so mail goes to the domain's own address (implicit MX). It has an AAAA record."},{"key":"dns","label":"Nameservers have IPv6","status":"pass","detail":"6 of 6 nameservers checked have an AAAA record, so IPv6-only resolvers can look the domain up.","hosts":[{"host":"a13-64.akam.net","ipv6":true},{"host":"a3-67.akam.net","ipv6":true},{"host":"a20-66.akam.net","ipv6":true},{"host":"a16-65.akam.net","ipv6":true},{"host":"a1-225.akam.net","ipv6":true},{"host":"a4-64.akam.net","ipv6":true}]}]},"https":{"status":"fail","problem":"redirect-no-ipv6","summary":"Redirects to oreilly.com, which has no IPv6 address — so IPv6 visitors end up needing IPv4 after all.","hops":[{"url":"https://sso.oreilly.com/","address":"2606:4700:440b::ac40:99f9","status":302,"tls":"valid"},{"url":"https://oreilly.com/","note":"redirects to oreilly.com, which has no IPv6 address"}]},"receiptId":"0ubQe-AyN9","reused":true,"measuredAt":"2026-11-01T16:40:39.929Z"}