The SUBFILESYSTYPE statement identifies each of the AF_INET or dual AF_INET/AF_INET6 socket physical file systems that are to run underneath the Common INET socket file system. SUBFILESYSTYPE is an optional statement.

If you plan to support more than one AF_INET or dual AF_INET/AF_INET6 physical file system, such as two TCP/IP networks, the CINET physical file system must be started to manage the multiple file systems

Changes to BPXPRMxx for sockets might also require changes in the user's TCP/IP security system. For more information, see Setting up TCP/IP security.