You can implement CONNX environment variables exclusively by entering variable/value pairs in a CNXPARMS partitioned data set member, or via the CNXCFG REXX command file CNXCFG and program CNXCFGB to update the CNXCFG VSAM KSDS, or by a combination of both methods. Defining CONNX environment variables via the CNXPARMS PDS member is easier than using the REXX exec file, but less secure, depending on the security rules protecting the CONNX.STASK.CNTL partitioned data set. Defining the CONNX environment variables in the CNXCFG KSDS provides an extra layer of protection, because the TSO/ISPF editor cannot view/update VSAM data sets.