{"kind":"host","input":"ycombinator.com","report":{"host":"ycombinator.com","checkedAt":"2026-11-02T03:30:19.625Z","a":{"status":"found","values":["108.138.64.111","108.138.64.8","108.138.64.90","108.138.64.45"],"ttl":60,"via":"Cloudflare","cname":[]},"aaaa":{"status":"found","values":["2600:9000:2508:d400:15:891f:4040:93a1","2600:9000:2508:1c00:15:891f:4040:93a1","2600:9000:2508:c200:15:891f:4040:93a1","2600:9000:2508:da00:15:891f:4040:93a1","2600:9000:2508:b800:15:891f:4040:93a1","2600:9000:2508:7200:15:891f:4040:93a1","2600:9000:2508:4800:15:891f:4040:93a1","2600:9000:2508:2c00:15:891f:4040:93a1"],"ttl":60,"via":"Cloudflare","cname":[]},"verdict":"dual-stack","www":{"host":"www.ycombinator.com","a":{"status":"found","values":["104.20.46.159","172.66.144.64"],"ttl":60,"via":"Cloudflare","cname":["www.ycombinator.com.cdn.cloudflare.net"]},"aaaa":{"status":"absent","via":"Cloudflare","cname":["www.ycombinator.com.cdn.cloudflare.net"]},"verdict":"ipv4-only"}},"readiness":{"grade":"B","summary":"Works over IPv6, with one gap: www doesn't fully work over IPv6.","reachabilityTested":true,"checks":[{"key":"web","label":"Website over IPv6","status":"pass","detail":"ycombinator.com has 4 IPv6 addresses and answers on every one we tested (4 more not tested).","addresses":[{"address":"2600:9000:2508:d400:15:891f:4040:93a1","result":"answers","port":443},{"address":"2600:9000:2508:1c00:15:891f:4040:93a1","result":"answers","port":443},{"address":"2600:9000:2508:c200:15:891f:4040:93a1","result":"answers","port":443},{"address":"2600:9000:2508:da00:15:891f:4040:93a1","result":"answers","port":443},{"address":"2600:9000:2508:b800:15:891f:4040:93a1","result":"not tested"},{"address":"2600:9000:2508:7200:15:891f:4040:93a1","result":"not tested"},{"address":"2600:9000:2508:4800:15:891f:4040:93a1","result":"not tested"},{"address":"2600:9000:2508:2c00:15:891f:4040:93a1","result":"not tested"}]},{"key":"www","label":"www over IPv6","status":"fail","detail":"www.ycombinator.com has no AAAA record."},{"key":"mail","label":"Mail servers (MX) have IPv6","status":"pass","detail":"Every mail server has an AAAA record.","hosts":[{"host":"aspmx.l.google.com","ipv6":true},{"host":"alt1.aspmx.l.google.com","ipv6":true},{"host":"alt2.aspmx.l.google.com","ipv6":true},{"host":"aspmx4.googlemail.com","ipv6":true}]},{"key":"dns","label":"Nameservers have IPv6","status":"pass","detail":"4 of 4 nameservers checked have an AAAA record, so IPv6-only resolvers can look the domain up.","hosts":[{"host":"ns-1411.awsdns-48.org","ipv6":true},{"host":"ns-1914.awsdns-47.co.uk","ipv6":true},{"host":"ns-225.awsdns-28.com","ipv6":true},{"host":"ns-556.awsdns-05.net","ipv6":true}]}]},"https":{"status":"fail","problem":"redirect-no-ipv6","summary":"Redirects to www.ycombinator.com, which has no IPv6 address — so IPv6 visitors end up needing IPv4 after all.","hops":[{"url":"https://ycombinator.com/","address":"2600:9000:2508:d400:15:891f:4040:93a1","status":301,"tls":"valid"},{"url":"https://www.ycombinator.com/","note":"redirects to www.ycombinator.com, which has no IPv6 address"}]},"receiptId":"HguaO-SL57","reused":true,"measuredAt":"2026-11-02T03:30:19.676Z"}