Example of Stateful Synchronization

In case of a failover, the following sequence of events occurs:

1. A PC user connects to the network, and the Active firewall creates a session for the user.
2. The Active firewall synchronizes with the Standby firewall. The Standby now has all of the user’s session information.
3. The administrator restarts the Active unit.
4. The Standby unit detects the restart of the Active unit and switches from Standby to Active.
5. The new Active firewall begins to send gratuitous ARP messages to the connected switches. It uses the same Virtual MAC address and IP address as the former Active firewall. No routing updates are necessary for downstream or upstream network devices.
6. When the PC user attempts to access a web page, the new Active firewall has all of the user’s session information and is able to continue the user’s session without interruption.