The Linux (POSIX) file security model is public by default, whereas the traditional Novell model is private. For a comparison of the two models, see Comparing the Linux and the Novell Trustee File Security Models
in the OES 2 SP3: Planning and Implementation Guide.
You can adjust the default permissions on Linux to more closely match the traditional Novell model by following the instructions in Aligning NCP and POSIX File Access Rights
in the OES 2 SP3: Planning and Implementation Guide.