{"kind":"host","input":"cancer.gov","report":{"host":"cancer.gov","checkedAt":"2026-11-15T17:08:32.743Z","a":{"status":"found","values":["129.43.254.39"],"ttl":7200,"via":"Cloudflare","cname":[]},"aaaa":{"status":"found","values":["2607:f220:41d:21c1::812b:fe27"],"ttl":7200,"via":"Cloudflare","cname":[]},"verdict":"dual-stack","www":{"host":"www.cancer.gov","a":{"status":"found","values":["23.48.203.176","23.48.203.184"],"ttl":20,"via":"Cloudflare","cname":["akamai-prod.cancer.gov.edgekey.net","e336944.dscb.akamaiedge.net"]},"aaaa":{"status":"found","values":["2600:1408:5400:35::17ca:e6c8","2600:1408:5400:35::17ca:e6e0"],"ttl":20,"via":"Cloudflare","cname":["akamai-prod.cancer.gov.edgekey.net","e336944.dscb.akamaiedge.net"]},"verdict":"dual-stack"}},"readiness":{"grade":"B","summary":"Works over IPv6, with one gap: its mail servers lack IPv6.","reachabilityTested":true,"checks":[{"key":"web","label":"Website over IPv6","status":"pass","detail":"cancer.gov has an AAAA record and answers on it.","addresses":[{"address":"2607:f220:41d:21c1::812b:fe27","result":"answers","port":443}]},{"key":"www","label":"www over IPv6","status":"pass","detail":"www.cancer.gov has 2 IPv6 addresses and answers on every one we tested.","addresses":[{"address":"2600:1408:5400:35::17ca:e6c8","result":"answers","port":443},{"address":"2600:1408:5400:35::17ca:e6e0","result":"answers","port":443}]},{"key":"mail","label":"Mail servers (MX) have IPv6","status":"partial","detail":"At least one mail server has no AAAA record (8 of 10 checked do).","hosts":[{"host":"nihcesxway.hub.nih.gov","ipv6":false},{"host":"nihcesxway2.hub.nih.gov","ipv6":false},{"host":"nihcesxway3.hub.nih.gov","ipv6":true},{"host":"nihcesxway4.hub.nih.gov","ipv6":true},{"host":"nihcesxway5.hub.nih.gov","ipv6":true},{"host":"nihcesxwayst01.hub.nih.gov","ipv6":true},{"host":"nihcesxwayst02.hub.nih.gov","ipv6":true},{"host":"nihcesxwayst03.hub.nih.gov","ipv6":true},{"host":"nihcesxwayst04.hub.nih.gov","ipv6":true},{"host":"nihcesxwayst05.hub.nih.gov","ipv6":true}]},{"key":"dns","label":"Nameservers have IPv6","status":"pass","detail":"3 of 3 nameservers checked have an AAAA record, so IPv6-only resolvers can look the domain up.","hosts":[{"host":"ns.nih.gov","ipv6":true},{"host":"ns2.nih.gov","ipv6":true},{"host":"ns3.nih.gov","ipv6":true}]}]},"https":{"status":"pass","summary":"Loads over IPv6 with a valid certificate after 1 redirect: HTTP 200.","hops":[{"url":"https://cancer.gov/","address":"2607:f220:41d:21c1::812b:fe27","status":301,"tls":"valid"},{"url":"https://www.cancer.gov/","address":"2600:1408:5400:35::17ca:e6c8","status":200,"tls":"valid"}]},"receiptId":"at5xYgs_g1","reused":true,"measuredAt":"2026-11-15T17:08:33.083Z"}