The Application Id identifies the web application in GeneXus Access Manager security module. Application Id is a property at version level and specifies the WEB GAM Application GUID of the KB.
The information is used when GAM Permissions are checked in runtime.
In F5 process, the "Application Id" information is copied to application.gam file (located in the virtual directory). See GAM - Applications Registration option for details on this process.
Only one WEB GeneXus Access Manager Application can be specified for each KB. Nevertheless, there can exist many WEB GAM Applications in a GAM Repository (see links below for more information).
What is Application Id property for?
Running a web application GeneXus Access Manager checks that this Application (identified by the Application Id) is defined within the GAM Repository where the user is connected to.
Because application.gam file stores the information of only one WEB GAM Application, one physical web app is associated to one WEB GAM Applications, so GAM retrieves the Application Id information and that is going to be used when permissions are checked. The permissions have to be defined for the GAM Applications retrieved in application.gam file.
Note: For SD Applications the "Client Application data" (Client Id and Client Secret information) of the GAM Applications is used to implement the security mechanism using Oauth.
GAM - Applications Registration option
Managing GAM Repositories and GAM Applications in GX development time