A method of providing telecommunication services includes generating fictitious contact information univocally associated with a telephone number assigned to a subscriber; and storing the fictitious contact information in a database, like an ENUM database. Responsive to a request, received from a requester, of a contact information corresponding to the telephone number and adapted to allow contacting over the Internet the subscriber assignee of the telephone number, the method includes having the database providing the fictitious contact information; and conditioning a resolution of the fictitious contact information for the provisioning of the contact information to the satisfaction of at least one security rule adapted to assess properties of at least one among the requester and the request. In a case that the request from the requester satisfies the at least one security rule, the method resolves the fictitious contact information and provides the requester with the contact information.