rdns

Quickly look up reverse DNS names. One of them or lots of them.

Look them up by IPv4 address:

$ rdns 192.0.43.7
# 192.0.43.7
192.0.43.7  icann.org.

Look them up by IPv6 address:

$ rdns 2001:500:88:200::8
# 2001:500:88:200::8
2001:500:88:200::8  iana.org.

Look up ranges of them:

$ rdns 192.0.43.7/29
# 192.0.43.7/29
192.0.43.1  43-1.any.icann.org.
192.0.43.2  43-2.any.icann.org.
192.0.43.3  43-3.any.icann.org.
192.0.43.4  43-4.any.icann.org.
192.0.43.5  43-5.any.icann.org.
192.0.43.6  43-6.any.icann.org.
192.0.43.7  icann.org.

Look them up by forward name:

$ rdns arin.net
# arin.net
2001:500:4:c000::43 www.arin.net.
2001:500:4:c000::44 www.arin.net.
199.43.0.43 www.arin.net.
199.43.0.44 www.arin.net.

Look them up by all of the above at once:

$ rdns 192.0.43.7 2001:500:88:200::8 192.0.43.7/29 arin.net
# 192.0.43.7
192.0.43.7  icann.org.
# 2001:500:88:200::8
2001:500:88:200::8  iana.org.
# 192.0.43.7/29
192.0.43.1  43-1.any.icann.org.
192.0.43.2  43-2.any.icann.org.
192.0.43.3  43-3.any.icann.org.
192.0.43.4  43-4.any.icann.org.
192.0.43.5  43-5.any.icann.org.
192.0.43.6  43-6.any.icann.org.
192.0.43.7  icann.org.
# arin.net
2001:500:4:c000::43 www.arin.net.
2001:500:4:c000::44 www.arin.net.
199.43.0.43 www.arin.net.
199.43.0.44 www.arin.net.

Installation

$ go get -u doof.net/cmd/rdns

Happy resolving.