A method of customer identification for personalizable Internet portals is described. The method identifies customers on the basis of the phone number of the calling party, in which the phone number and service request is transmitted from the terminal via the access network to a proxy server, which in turn is responsible for converting the protocol between the access network and Internet, in which depending on the service request, the proxy server inserts a customer ID into the service request and the customer ID is called up by the proxy server from a customer registry based on the MSISDN, so that at the portal the ID can be taken from the service request and the authorization of the customer can be verified through an inquiry sent to the customer registry at which point the service request of the customer is fulfilled.