A network system includes first nodes and a second node. Each first node is directly communicatively connected to the second node, or each first node is indirectly communicatively connected to the second node through another first node. The second node includes a network layer and an application layer. When a new node desires is joining the first nodes, the network layer sends an update signal including first network address information of the new node. The application layer is configured to connect to a database and perform an authentication on the first network address information of the new node based on a node list in the database. When the new node passes the authentication, the application layer stores the update signal in the database.