an ip telephone number query system includes a terminal , a web server , and an enum server . the terminal displays a call recipient profile hypertext markup language that is assigned a html document file name . the web server includes a phonebook searcher that has a plurality of call recipient profile htmls , and returns a selected call recipient profile html in response to a request from the terminal . the enum server has a database , a query issuer and a reversed query issuer . the database stores a plurality of naptr resource records in association with an enum domain name , each naptr resource record containing a uri that at least includes a telephone number and a html document file name . the query issuer searches the database in response to a query by an enum domain name and returns a naptr resource record corresponding to the enum domain name . the reversed query issuer searches the database in response to a query by a uri of a html document file name and returns a uri of a telephone number corresponding to the enum domain name having the uri of the html document file name .