High availability network security systems

1. A recovery method for a network security system, the method comprising:

providing a master device and a backup device within a cluster of network security devices;

providing the backup device with state information for the master device, the state information relating to an ongoing set of connections through the master device and the state information including session information and keying material associated with secure remote connections;

communicating control messages relating to a failure state of the master device and the backup device over an out-of-band connection and, when the out-of-band connection fails, communicating the control messages over an in-band connection;

detecting failure in the cluster based on the control messages; and

using the state information to recover from the failure by recovering the ongoing set of connections at the backup device,

wherein the master device and the backup device are configured to simultaneously act as a backup device and a master device, respectively, for an additional set of ongoing connections.

2. The method of claim 1 wherein detecting failure in the cluster comprises monitoring paths within the cluster.

3. The method of claim 1 wherein the master device and the backup device are elected in advance of the failure.

4. The method of claim 1 , wherein the state information relates to an ongoing file transfer protocol (ftp) connection.

5. The method of claim 1 , wherein the state information relates to an ongoing virtual private network (VPN) connection.

6. A network security device comprising:

ports for communicating on a network; and

a controller configured to

operate as a master device for a first set of connections, including transmitting state information for the first set of connections to one or more backup devices, the state information including session information and keying material associated with secure remote communications;

communicate control messages relating to a failure state of the master device and the one or more backup devices over an out-of-band connection and, when the out-of-band connection fails, communicate the control messages over an in-band connection; and

simultaneously operate as a backup device for a second set of connections, including receiving state information from a master device associated with the second set of connections, detecting failure of the associated master device, and using state information received from the associated master device to recover from the failure.

7. The network security device of claim 6 wherein the ports for communicating on the network include redundant network ports.

8. The network security device of claim 6 , wherein the state information relates to an ongoing file transfer protocol (ftp) connection.

9. The network security device of claim 6 , wherein the state information relates to an ongoing virtual private network (VPN) connection.

10. A network security system comprising:

a master device configured to support a first group of connections including maintaining state information that relates to ongoing connections through the master device, the state information including session information and keying material associated with secure remote connections with the master device; and

a backup device configured to receive the state information from the master device relating to the first group of connections, to detect a failure of the master device, and to use the state information to recover from the failure by recovering the ongoing first group of connections, the backup device recovering the state information and detecting the failure of the master device using control messages communicated via out-of-band connections and, when the out-of-band connections fail, communicating the control messages over an in-band connection,

wherein the master device and the backup device are configured to simultaneously act as a backup device and a master device, respectively, for additional groups of ongoing connections.

11. The system of claim 10 wherein the master device and the backup device each contain control information necessary to support the connections.

12. The system of claim 10 wherein the master device and the backup device include a messaging engine for communicating the control messages.

13. The system of claim 12 where the messaging engine includes redundant messaging interfaces for transmitting and receiving the control messages in the out-of-band connection.

14. The network security system of claim 10 , wherein the state information relates to an ongoing file transfer protocol (ftp) connection.

15. The network security system of claim 10 , wherein the state information relates to an ongoing virtual private network (VPN) connection.

16. A method for increasing throughput of network security devices, the method comprising:

providing a network device connected to a plurality of network devices divided into a first and a second group; and

configuring the network device to support connections within the first group and backup connections within the second group, the backup connections being provided for by receiving control messages that include state information from another network device, the state information relating to ongoing connections in the second group and using the state information to recover from a failure in the another network device without breaking the ongoing connections in the second group, the control messages being communicated over an out-of-band connection, and, when the out-of-band connection fails, the control messages being communicated over an in-band-connection.