PROFILE.TCPIP search order

During initialization of the TCP/IP stack, system operation and configuration parameters for the TCP/IP stack are read from the configuration file PROFILE.TCPIP. As shown in Table 1, the search order used by the TCP/IP stack to find PROFILE.TCPIP involves both explicit and dynamic data set allocation as follows:
Note: Explicitly specifying the PROFILE DD statement in the TCPIPROC JCL is the recommended way to specify PROFILE.TCPIP. If this DD statement is present, the data set it defines is explicitly allocated by MVS™ and no dynamic allocation is done. If this statement is not present, the search order continues to use dynamic allocation for the PROFILE.TCPIP.