What's the reverse DNS command line utility?

Solution 1:

dig and host should be what you're looking for ;)

http://www.unix.com/unix-dummies-questions-answers/9866-nslookup-linux.html

On *nix system you can do this command : dig -x [address]

Alternatively you can add +short at the end of the dig command to output only the dns result.

On Windows, use nslookup

EDIT : nslookup work too on *nix systems. More infos on nslookup command whether it seems to have been replace since a while now : http://linuxreviews.org/man/nslookup/

Solution 2:

On *nix you can use:

dig -x [address]

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Solution 3:

On most of the Linux systems that I am aware of you can use:

 nslookup <ip-number EX: 127.0.0.1>

will work on the command line.

Come to think of it, isn't nslookup available on Windows XP?

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Solution 4:

Try "host"

• Forward lookup with host:

  $ host google-public-dns-b.google.com.
  google-public-dns-b.google.com has address 8.8.4.4
  google-public-dns-b.google.com has IPv6 address 2001:4860:4860::8844
  

• Reverse lookup with host:

  $ host 8.8.4.4
  4.4.8.8.in-addr.arpa domain name pointer google-public-dns-b.google.com.
  

Similar to dig

• Forward lookup with dig:

  $ dig google-public-dns-b.google.com. +short
  8.8.4.4
  

• Reverse lookup with dig:

  $ dig -x 8.8.4.4 +short
  google-public-dns-b.google.com.
  

Try "rdt"

It takes a little more setup. But if you do this, then you can run this "rdt" PHP script from the command line and it's quite wonderful. It does a few back and forth trips between forward and reverse lookups.

Download from here: https://github.com/grawity/code/blob/master/net/rdt

Example. This is what it looks like when it's working:

$ rdt google-public-dns-b.google.com.
google-public-dns-b.google.com. = 2001:4860:4860::8844, 8.8.4.4
   2001:4860:4860::8844 = dns.google
      dns.google = 2001:4860:4860::8844, 2001:4860:4860::8888, 8.8.4.4, 8.8.8.8
         2001:4860:4860::8888 = dns.google
         8.8.8.8 = dns.google
   8.8.4.4 = dns.google

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Solution 5:

This question already has a million answers, but I'm gonna add another one. Here's a little function I wrote for easily doing reverse DNS with dig. Add this to your ~/.bashrc file, reload your shell, and then you can do reverse DNS lookups with revdns 1.2.3.4:

function revdns() {
    octets=""
    addr="in-addr.arpa"

    # split the IP address into an array of octets
    IFS="." read -r -a octets <<< "$1"

    # add each octet to our $addr string in reverse order
    for octet in "${octets[@]}"; do
         addr=$octet"."$addr
    done

    # run a DNS pointer lookup with dig
    # `+short` makes dig's output very terse (un-verbose)
    # `"${@:2}"` passes any extra params from this command to dig
    dig ptr +short $addr "${@:2}"
}

Reverse DNS lookups are done by checking the pointer (PTR) records. If you wanna do reverse DNS for "1.2.3.4", you have to lookup pointer records for "4.3.2.1.in-addr.arpa". My function takes in an IP address, reverses the order of the octets (i.e. changes it from 1.2.3.4 to 4.3.2.1), and then uses dig to execute the PTR lookup I just described.

You can, of course, just use nslookup 1.2.3.4 if you have it, but I prefer this dig-based solution because it uses the OS' DNS servers instead of nslookup-provided ones (if you want, by the way, you can add additional dig flags when you call revdns, and they will get passed to dig)