Enter the data set name of the TCP/IP port member and, optionally, its volume location.

You have indicated that your current PORT and PORTRANGE configuration statements are exclusively defined in a separate MVS data set file. This file will be parsed by msys during the refresh process and the data collect will be shown on the customization panels.

msys for Setup needs to know the exact location of this file containing the PORT and PORTRANGE statements. You should specify the fully qualified name of this file. It is most likely that the file is cataloged and you do not need to specify the volume serial. If it is not cataloged, you will need to also specify the volume serial to allow msys to locate it.