Provided are a network scanner and a method of organizing and maintaining a network scanning system, which makes a list of users who are currently connected to the network scanner and automatically maintains the users connections to the network scanner even when an Internet protocol (IP) address of the network scanner changes. The method involves (a) enabling the computer to transmit user information to the network scanner, the user information being input by a user of the computer with the use of a client program installed in the computer; (b) enabling the network scanner to receive the user information from the client program; and (c) enabling the network scanner to make a user list by using the received user information.