2620:101:2011:300::3fc

Reverse address entry: c.f.3.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.3.0.1.1.0.2.1.0.1.0.0.2.6.2.ip6.arpa

2620:101:2011:300::3fc has no DNS entries .

Explore by label: c . f . 3 . 0 . 0 . 0 . 0 . 0 . 0 . 0 . 0 . 0 . 0 . 0 . 0 . 0 . 0 . 0 . 3 . 0 . 1 . 1 . 0 . 2 . 1 . 0 . 1 . 0 . 0 . 2 . 6 . 2 . ip6 . arpa

RIPE6 c.f.3.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.3.0.1.1.0.2.1.0.1.0.0.2.6.2.ip6.arpa
CNAMEc.f.3.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.3.0.1.1.0.2.1.0.1.0.0.2.6.2.ip6.arpa.eu.iphmx.com expired since 6 days, 19 hours
Show 1 expired records

This top-level domain has no publically available whois server. Try going to www.nic.arpa.