Disclosed is a data transfer system capable of efficiently transferring broadcast and multicast packets when a virtual network is configured in a network arranged over multiple domains. The data transfer system is equipped with: a first data transfer server for tunnel end points which belong to a first domain; and a second data transfer server for tunnel end points which belong to a second domain. The first data transfer server, upon receiving a packet from a tunnel end point in the first domain, transfers the packet to the second data transfer server and to the tunnel end points in the first domain other than the packet transfer source tunnel end point, and the second data transfer server, upon receiving the packet from the first data transfer server, transfers the packet to the tunnel end points in the second domain.