IPv4 ... ... via ipip.ooo IPv6 ... ... via ipip.ooo DNS ... ... why

$ curl ipip.ooo $ curl -4 ipip.ooo $ curl -6 ipip.ooo $ curl ipip.ooo/country $ curl -L ipip.ooo/dns $ curl -L ipip.ooo/dnscountry ... ... Query GET https://4.ipip.ooo GET https://6.ipip.ooo GET https://ipip.ooo/ip/8.8.8.8