Dig is a DNS lookup utility provided by ISC. This page is a simple web interface for dig.
$ dig 2001:67c:2ac0::2 PTR ; <<>> DiG 9.11.3-1ubuntu1.2-Ubuntu <<>> 2001:67c:2ac0::2 PTR ;; global options: +cmd ;; Got answer: ;; ->>HEADER<<- opcode: QUERY, status: NXDOMAIN, id: 14415 ;; flags: qr rd ra ad; QUERY: 1, ANSWER: 0, AUTHORITY: 1, ADDITIONAL: 1 ;; OPT PSEUDOSECTION: ; EDNS: version: 0, flags:; udp: 4096 ;; QUESTION SECTION: ;2001:67c:2ac0::2. IN PTR ;; AUTHORITY SECTION: . 75022 IN SOA a.root-servers.net. nstld.verisign-grs.com. 2018102201 1800 900 604800 86400 ;; Query time: 2 msec ;; SERVER: 139.162.69.5#53(139.162.69.5) ;; WHEN: Mon Oct 22 20:37:44 UTC 2018 ;; MSG SIZE rcvd: 120