Controlling how routing changes affect active sessions

Dynamic routing changes can occur while a FortiGate is processing traffic. Routing changes that affect the routes being used for current sessions, may affect how the FortiGate continues to process the session.You can control how active sessions are affected when dynamic routing changes occur that affects the routes the active sessions are using.

You can configure whether the FortiGate maintains the original routing for the sessions that are using the affected routes, or applies the routing table changes to the active sessions, which may cause destinations to change.

To configure how dynamic routing changes affect active sessions - CLI:

config system interface

edit <interface_name>

set preserve-session-route {enable | disable}

next

where you set the following variables:

CLI option	Description
<interface_name>	The name of the interface where you want to configure how dynamic routing changes affect active sessions running through it.
enable	All sessions passing through the interface when the routing changes occur, are allowed to finish and aren't affected by the routing changes.
disable (default)	When a routing change occurs, the new routing table is applied to the active sessions passing through the interface. The routing changes may cause the destinations of the sessions to change.