The logon client for the Application Server is defined using the following procedure.
If the flag Mandatory Logon Data has been set in a service/service node in transaction SICF, the system uses the client that is entered there.
If this is not the case, but the HTTP request contains the client in the HTTP header (as a header or a form field), you log on to the system using this client.
If a client is entered for the service in transaction SICF, this client is used.
If no client is defined with this procedure, then the default client of the application server is used.