Customize member MFA in the CNTL data set. This is the started task JCL procedure for Mainframe Access server. Use the ISPF change command to change HLQ to your qualifier ( hlq ).
If you are using IBM's TCP/IP, overtype TCPIP.OS390.TCPDATA with the name of your installation's "TCPIP.DATA" data set ( tcpdata ). This is the data set used by client programs to obtain the name of the TCP/IP started task and other installation-dependent TCP/IP information.