The present invention discloses a method for advertising routing information, and embodiments of the present invention further provide a virtual private network server device, an IP edge node device, and a client-based virtual private network system. In the technical solutions of the present invention, a virtual private network server first collects MAC address routing information of each site on a local virtual private network and then sends MAC address routing information of each site except a destination site in a unicast manner to a customer edge node that corresponds to each site on the virtual private network. This solves the problem that CE nodes in sites on the virtual private network cannot exchange routing information with each other by using a routing protocol because multicast packets are filtered by an access node of the data center network.