When searching for configuration files, you can explicitly tell TCP/IP where most configuration files are by using DD statements in the JCL procedures or by setting environment variables. Otherwise, you can let TCP/IP dynamically determine the location of the configuration files, based on search orders shown in Table 1.
For example, in Table 1, for the FTP server application, if the installation did not code the //SYSFTPD DD statement, the FTP server would search for jobname.FTP.DATA, then file /etc/ftp.data, then data set SYS1.TCPPARMS(FTPDATA), and finally hlq.FTP.DATA.