To find TCPIP.DATA, NPF follows a standard search sequence. It reads each instance of TCPIP.DATA it can find, in order, until it finds values for both the TCP/IP configuration statements. It uses the first value that it finds for each statement. If an allocation fails, the data set does not exist, or the data set is not available, NPF goes to the next data set in the sequence. The search ends when it finds values for both the TCP/IP configuration statements or when all data sets have been checked. The search order is:

1. The data set pointed to by the DD statement //SYSTCPD.
2. A data set with the name of jobname.TCPIP.DATA, where jobname is the jobname for the NPF capture point application or the TSO user ID for the TSO session (panels).
3. A data set with the name of SYS1.TCPPARMS(TCPDATA).
4. A data set with the name of hlq.TCPIP.DATA, where hlq is the value set by a DATASETPREFIX statement found in a prior TCPIP.DATA, or the system default value of TCPIP.

You can also find information about the native MVS™ environment TCPIP.DATA search order, and the system default in z/OS Communications Server: IP Configuration Guide.