To provide a communication system that enables an information provider to provide users best information in terms of contents, volumes and a speed for providing the information by considering attributes of the users.

A communication system has a user terminal 2 that transmits to a data providing server 4, a data request and an IP address accommodating a user attribute code to be used for getting user attribute data to represent the attributes of the users. The data providing server 4 gets the user attribute data on the basis of the user attribute code stored in the IP address which is received when the data request is implemented, executes a specified process for content data related with the request by using the user attribute data, and transmits the processed content data to a user terminal 2.