Abstract: A virtual private network device enables individual machines at a remote subnet to be visible and addressable from a central site by establishing a private address range for the remote machines, forming a virtual private network tunnel from the virtual private network device to the central site, and communicating the private address range to the central site to enable connections from the central site to individual machines on the remote subnet.

Abstract: In a hardware client for remote logon to a network, a two layer authentication protocol enables authorized users to log on while discouraging unauthorized users. The hardware client prevents logging on to the network if the hardware client is stolen. The hardware client itself is authenticated in the first authentication layer in order to establish a link to the network. Then a client computer authenticates in a second layer and further establishes a secure connection to the network. If the power of the hardware client goes off (as it would if or example it were unplugged for transport), then the authentication is not saved and therefore is lost. The hardware client must be reauthenticated before it can be used again.

Abstract: A virtual private network device enables individual machines at a remote subnet to be visible and addressable from a central site by establishing a private address range for the remote machines, forming a virtual private network tunnel from the virtual private network device to the central site, and communicating the private address range to the central site to enable connections from the central site to individual machines on the remote subnet.

Abstract: A virtual private network device enables individual machines at a remote subnet to be visible and addressable from a central site by establishing a private address range for the remote machines, forming a virtual private network tunnel from the virtual private network device to the central site, and communicating the private address range to the central site to enable connections from the central site to individual machines on the remote subnet.

Abstract: In a virtual private network, a plurality of concentrators form an interface to provide client/remote site access to a private network over a public network. The plurality of concentrators are grouped into a virtual cluster. Each concentrator in the virtual cluster has an IP address and the virtual cluster has a virtual IP address. In operation, one of the plurality of concentrators assumes the virtual IP address and acts as the master device in the cluster. When a client attempts a connection to the private network, the client addresses an initial request to the virtual IP address. The master device responds to the client request by transmitting to the client the IP address of a concentrator in the cluster selected to handle the connection.

Abstract: A client device establishes a virtual private network connection with a central site or network through a master concentrator. The master concentrator transmits state information, relating to the virtual private network connection, to a backup concentrator. In the event the master concentrator fails during a communications session between the client device and the network, the backup concentrator maintains the communication session between the client device and the network over the virtual private network connection using the connection state information received from the master concentrator. Such a configuration allows for failover of a virtual private network connection from the master concentrator to the backup concentrator without requiring the client device to re-establish the virtual private network connection with the central site or network. The configuration also allows the client device to maintain an existing communications session with the network.