Method and apparatus for locating naming discrepancies

Abstract

A system is provided that polls one or more caching nameservers and compares their results to a trusted or standard set of data. The set of data may be, for example, stored in a computer system or distributed among several computer systems. In one aspect, the system comprises a discrepancy detector that detects discrepancies between one or more copies of mapping information. Mapping information may be, for example, mapping stored on a Domain Name System (DNS).

1 . A method for locating a discrepancy in mapping information that maps an identifier to a particular resource, the method comprising acts of:
 determining a first mapping;   determining a second mapping; and   comparing the first mapping to the second mapping and identifying at least one discrepancy between the first and second mapping.   
     
     
         2 . The method of  claim 1 , wherein the act of determining a second mapping comprises acts of querying a nameserver and receiving a response from the nameserver, the response containing the second mapping. 
     
     
         3 . The method of  claim 1 , wherein the act of determining a first mapping comprises an act of obtaining an authoritative mapping from an authoritative source. 
     
     
         4 . The method of  claim 3 , wherein the authoritative source is at least one of
 an authoritative nameserver; and   a database storing a plurality of authoritative mappings.   
     
     
         5 . The method of  claim 1 , further comprising an act of reporting the at least one discrepancy to a user. 
     
     
         6 . The method of  claim 1 , wherein the first mapping is a first namespace mapping that maps a first name to a first resource and the second mapping is a second namespace mapping that maps a second name to a second resource. 
     
     
         7 . The method of  claim 6 , wherein the first namespace mapping is stored on an authoritative nameserver and the act of determining a first mapping comprises an act of obtaining the first mapping from the authoritative nameserver. 
     
     
         8 . The method of  claim 6 , wherein the act of determining a second mapping comprises acts of querying a nameserver and receiving a response from the nameserver, the response containing the second mapping. 
     
     
         9 . The method of  claim 2 , further comprising an act of compiling a list of nameservers to be queried. 
     
     
         10 . The method of  claim 8 , wherein the act of querying a nameserver comprises an act of requesting at least one namespace mapping record from the nameserver. 
     
     
         11 . The method of  claim 9 , wherein the act of compiling a list of at least one nameserver comprises acts of:
 sending a namespace mapping resolution query to a plurality of network nodes;   waiting for one or more responses from the plurality of network nodes; and   determining whether a network node in the plurality of network nodes is a nameserver.   
     
     
         12 . The method of  claim 11 , wherein the act of determining comprises an act of determining whether the network node in the plurality of network nodes is a nameserver based on a format of one or more responses received from the network node. 
     
     
         13 . The method of  claim 11 , wherein the act of determining comprises an act of determining that a network node in the plurality of nodes is not a nameserver if the network node does not respond to the namespace mapping resolution query. 
     
     
         14 . The method of  claim 9 , wherein the act of compiling a list of at least one nameserver comprises an act of:
 listening for a request from a non-authoritative nameserver to an authoritative nameserver; and   when the request is detected, adding the non-authoritative nameserver to a list of nameservers.   
     
     
         15 . The method of  claim 14 , wherein the request is a resolve request. 
     
     
         16 . A method for discovering nameservers, comprising acts of:
 sending a namespace mapping resolution query to a plurality of network nodes;   waiting for one or more responses from at least one of the network nodes; and   determining whether a network node in the plurality of network nodes is a nameserver.   
     
     
         17 . The method of  claim 16 , wherein the act of determining comprises an act of determining whether a network node in the plurality of network nodes is a nameserver based on a format of the response from the network node. 
     
     
         18 . The method of  claim 16 , wherein the act of determining comprises an act of determining that a network node in the plurality of nodes is not a nameserver if the network node does not respond to the namespace mapping resolution query. 
     
     
         19 . A method for discovering nameservers, comprising acts of:
 listening for a request from a non-authoritative nameserver to an authoritative nameserver; and   when the request is detected, adding the non-authoritative nameserver to a list of nameservers.   
     
     
         20 . The method of  claim 19 , wherein the request is a resolve request.