The base resolver configuration file contains TCPIP.DATA statements. In addition to resolver directives, it is referenced to determine, among other things, the data set prefix (DATASETPREFIX statement's value) to be used when trying to access some of the configuration files.
The search order used to access the base resolver configuration file is as follows:
If defined, the resolver GLOBALTCPIPDATA setup statement value is used. For a description of the GLOBALTCPIPDATA statement, see The resolver and the global TCPIP.DATA file.
The search continues for an additional configuration file. The search ends with the next file found.
The value of the environment variable is used. This search will fail if the file does not exist or is allocated exclusively elsewhere.
The data set allocated to the ddname SYSTCPD is used. In the z/OS® UNIX environment, a child process does not have access to the SYSTCPD DD. This is because the SYSTCPD allocation is not inherited from the parent process over the fork() or exec function calls.
userid is the user ID that is associated with the current security environment (address space or task/thread)
If defined, the resolver DEFAULTTCPIPDATA setup statement value is used. For a description of the DEFAULTTCPIPDATA statement, see The resolver and the global TCPIP.DATA file.
Any TCPIP.DATA statements that have not been found will have their default values, if any, assigned.