Solaris NFS servers support an auxiliary NFSv3 ACL protocol that
never became an official part of the NFS version 3 protocol.
This protocol extension allows applications on NFS clients to
manipulate POSIX Access Control Lists on files residing on NFS
servers. NFS servers enforce POSIX ACLs on local files whether
this protocol is available or not.

This option enables support in your system's NFS server for the
NFSv3 ACL protocol extension allowing NFS clients to manipulate
POSIX ACLs on files exported by your system's NFS server. NFS
clients which support the Solaris NFSv3 ACL protocol can then
access and modify ACLs on your NFS server.

To store ACLs on your NFS server, you also need to enable ACL-
related CONFIG options for your local file systems of choice.

If unsure, say N.