Abstract: A system and method for providing ad hoc controlled user access to wireless and wireline IP communication networks while maintaining privacy for users and traceability for network providers. The method includes an authentication interface accepting user credentials, and a validation entity for credential verification and access authorization. The credentials include a unique identifier and a system generated password. The unique identifier is associated with a personal entity of the user such as a cellular telephone. The password is transmitted to the user through a SMS message to his cellular telephone. The user's Internet session is monitored by the system and all records are indexed by his cellular telephone number. The system and method therefore permit fast and traceable access for guest users at networks where they are were not previously known. Alternatively, users do not provide their unique identifiers such as cellular telephone numbers which are instead already stored in the system.