Elements of security in an APPC network

When Distributed Relational Database Architecture (DRDA) is used, the data resources of each system in the DRDA environment should be protected.

To protect data resources of each system in the DRDA environment, you can use three groups of security elements that are controlled by the following parameters:

  • For system-related security or session, the LOCPWD parameter is used on each system to indicate the system validation password to be exchanged between the client and server systems when an Advanced Program-to-Program Communication (APPC) session is first established between them. Both systems must exchange the same password before the session is started. (On System/36, this password is called the location password.) In an APPC network, the LOCPWD parameter on the Create Device Description (APPC) (CRTDEVAPPC) command specifies this password. Devices are created automatically using APPN, and the location password on the remote location list specifies a password that is used by the two locations to verify identities. Use the Create Configuration List (CRTCFGL) command to create a remote location list of type (*APPNRMT).
  • For user-related or location security, the SECURELOC parameter is used on each system to indicate whether it (as a server system) accepts incoming access requests that have their security already verified by the client system or whether it requires a user ID and encrypted password. In an APPC network, the SECURELOC parameter on the Create Device Description (APPC) (CRTDEVAPPC) command specifies whether the local system allows the remote system to verify security. Devices are created automatically using APPN, and the secure-location on an APPN remote Configuration List is used to determine if the local system allows the remote system to verify user security information. The SECURELOC value can be specified differently for each remote location.

    The SECURELOC parameter is used with the following security elements:

    • The user ID sent by the client system, if allowed by this parameter
    • The user ID and encrypted password, if allowed by this parameter
    • The server system user profiles, including default user profiles

    For more information, see the topic DRDA server security in an APPC network.

  • For object-related security, the DDMACC parameter is used on the Change Network Attributes (CHGNETA) command to indicate whether the files on the IBM i operating system can be accessed at all by another system and, if so, at which level of security the incoming requests are to be checked.
    • If *REJECT is specified on the DDMACC parameter, all DRDA requests received by the server system are rejected.
    • If *OBJAUT is specified on the DDMACC parameter, normal object-level security is used on the server system.
    • If the name of an exit program (or access control program) is specified on the DDMACC parameter, an additional level of security is used. The user exit program can be used to control whether a given user of a specific client system can use a specific command to access (in some manner) a specific file on the server system. (See the DDM server access control exit program for additional security topic for details.)
    • When a file is created on the server system using DRDA, the library name specified contains the file. If no library name is specified on the DRDA request, the current library (*CURLIB) is used. The default file authority allows only the user who created the file or the server system's security officer to access the file.

Most of the security controls for limiting remote file access are handled by the server system. Except for the user ID provided by the client system, all of these elements are specified and used on the server system. The client system, however, also limits access to server system files by controlling access to the DRDA file on the client system and by sending the user ID, when needed, to the server system.