0 to 1024
Yes. If ngroups_max is set to an invalid value, it is automatically reset to the closest legal value. For example, if it is set to less than zero, it is reset to 0. If it is set to greater than 1024, it is reset to 1024.
Review the following considerations if you are using NFS AUTH_SYS authentication and you want to increase the default ngroups_max value:
If ngroups_max is set to 16 or if the client's AUTH_SYS credential that is provided has 15 or fewer groups, the client's group information is used.
If ngroups_max is set to greater than 16 and the client's AUTH_SYS credential from the name server contains exactly 16 groups, the maximum allowed, the NFS server consults the name server and matches the client's UID to a user name. Then, the name server computes a list of groups to which the user belongs.