Reverse dns lookup tool

Perform a reverse lookup:

What is this? provides a quick access to reverse name resolution. With this site you can translate an IP address with his hostname.

Simply fill the following form and press the "Send Query" button to see the result for your reverse dns lookup.

What is a reverse lookup?

The DNS system is delegated to translate hostnames into IP addresses to permit a quick connection between computers. The same system is also very useful to perform a reverse process: translate ip addresses into hostnames. This, also if it might be considered a secondary problem, is very important, since it's vital for some services (like Mail transport agents).

The reverse resolution process starts with an ip address, which, in our example, can be considered as X.Y.Z.K (where the four letters are a visual representation of four numbers). This ip address needs to be translated into an hostname via the DNS. DNS systems normally handle domain names and hostnames as query objects, so the IP address is translated into an hostname under the zone. The corresponding hostname is obtained reversing the four number's order and appending the main zone name: This is the hostname that the DNS is queried to translate via a PTR query.

The process schema is the following

  • ip address: X.Y.Z.K
  • ip address in reverted order: K.Z.Y.X
  • zone append:
  • query the dns for a record PTR

At this point you can know the hostname corresponding to that IP address. (this site provides a full ip address reversion, so do not insert into the form the reverted ip, insert it in the normal octect order)

RDNS Know How

  • Wikipedia
    This article explains what is a reverse dns lookup from a technical point of view
  • NTChosting
    Explains all the process of reverse resolution with a good graphical example
  • RIPE
    RIPE delegation table and explanations


  • DoxPara
    Check if your name server is vulnerable to a very popular bug
  • Dynamic Dns
    Offers a free service for binding your DSL-ip address with a name
  • DNS Stuff
    Provides a good set of tools for sys admins
  • BIND
    This is really "THE" name server software

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