How can I increase the state table size
The state table size may be set in the WebGUI at System > Advanced on the Firewall/NAT tab. Enter a new value in the Firewall Maximum States box and then click Save.
The default size of the state table is set to use 10% of the system RAM. Each state consumes approximately 1KB of RAM. So for 1,000,000 states, 1GB of RAM would be required just for states.
Each connection flowing through the firewall will consume two states: One state when entering, and one state when exiting. As a result, the highest number of connections possible through the firewall is approximately half the total size of the state table. For example if the maximum size of the state table is 500,000 then approximately 250,000 user connections could be made through the firewall.
Connections terminating at the firewall, such as connections to the GUI, gateway monitoring traffic, VPN outer tunnel traffic, and so on each would consume only a single state as they only involve a connection to or from one interface.