You have 2 possibilities:

  -  from the NW User GUI (Windows)

  - via the nsrports command. please see the Command Line Reference manual for details.

and you want that because of what exactly? as you'd have to count exactly for example how many ports would need to configured at minimum, for example when a NW module backup is involved, or backups devices. Or a client vs. a storage node vs. the backup server.

see example calculations stated in the nw19.7 security guide:

https://www.dell.com/support/manuals/en-us/networker/nw_p_security_config/determining-service-port-requirement-examples?guid=guid-2e78456d-6c90-4ad2-8f5a-9d84192f8a4b&lang=en-us