Use the check boxes within the Aggressive Mode section of the Security tab to specify whether ClearSCADA is to accept Aggressive Mode requests from, or issue Aggressive Mode requests to, this outstation:
- Accept Requests—Select this check box if ClearSCADA is to accept Aggressive Mode requests from the outstation. With such requests, the outstation includes the necessary authentication data in the same message as the critical request.
Clear the Accept Requests check box if ClearSCADA is to reject any Aggressive Mode requests. ClearSCADA may also send a diagnostics message indicating that it does not accept Aggressive Mode messages (see Specify the Maximum Error Count).
- Issue Requests—Select this check box if ClearSCADA is to send Aggressive Mode requests to the outstation. With such requests, ClearSCADA includes the necessary authentication data in the same message as the critical request.
Clear the Issue Requests check box if ClearSCADA is not to send Aggressive Mode requests. The outstation will challenge the critical requests that it receives from ClearSCADA.
NOTE: If ClearSCADA issues an Aggressive Mode request to an outstation that does not accept Aggressive Mode requests, the outstation will generate an error (provided that the outstation has not exceeded its maximum error count). On detecting the error, ClearSCADA will raise an alarm, and will then issue the request, and all subsequent critical requests in that session, without using Aggressive Mode. However, when ClearSCADA makes a new connection attempt, for example, after a Main-Standby changeover, driver restart, or configuration change, it will attempt to use Aggressive Mode again. This means the Aggressive Mode error will be repeated on every new connection.
If an Aggressive Mode error occurs, correct the configuration in the relevant device so that the appropriate mode of DNP3 Secure Authentication is used.
It will not use Aggressive Mode for any further critical requests that it issues to the outstation during that session. However, on subsequent connections, ClearSCADA will attempt to use Aggressive Mode again.
If ClearSCADA has detected an error and is no longer using Aggressive Mode, you will need to configure the relevant device to use the appropriate mode of DNP3 Secure Authentication. This will allow ClearSCADA to communicate with the device more efficiently.
If you do not correct the configuration, ClearSCADA will attempt to use Aggressive Mode on each new connection attempt (for example, after a Main-Standby changeover, driver restart, or configuration change.) This means that the error-detection and switch to non-Aggressive Mode will occur each time a new connection is used, which makes the communications process less efficient.