By default existing connections are not closed if a Real Server fails. This can lead to issues with Outlook clients if an Exchange CAS server fails. A solution to this is to enable the Drop Connections on RS Failure option which can be found on the System Configuration > Miscellaneous > L7 Configuration screen in the WUI.

When this option is enabled, LoadMaster tracks all the incoming connections and which Real Servers they are connected to. When a Real Server fails, all connections to the Real Server are immediately dropped, forcing the connections to reconnect to a different Real Server.

Enabling this option has the added benefit of allowing relatively higher Idle Connection Timeout values to be set as the danger of the client retaining a connection to a failed server is removed.