Trusted Extensions Software and NFS Protocol Versions

Trusted Extensions software recognizes labels on NFS Version 3 (NFSv3) and NFSv4. You can use one of the following sets of mount options:

vers=4 proto=tcp
vers=3 proto=tcp
vers=3 proto=udp

Trusted Extensions has no restrictions on mounts over the tcp protocol. In NFSv3 and NFSv4, the tcp protocol can be used for same-label mounts and for read-down mounts. Read-down mounts require a multilevel port (MLP).

For NFSv3, Trusted Extensions behaves like the Oracle Solaris OS. The udp protocol is the default for NFSv3, but udp is used only for the initial mount operation. For subsequent NFS operations, the system uses tcp. Therefore, read-down mounts work for NFSv3 in the default configuration.

In the rare case that you have restricted NFSv3 mounts to use the udp protocol for initial and subsequent NFS operations, you must create an MLP for NFS operations that use the udp protocol. For the procedure, see How to Configure a Multilevel Port for NFSv3 Over udp.

A host that is configured with Trusted Extensions can also share its own file systems with unlabeled hosts. A file or directory that is exported to an unlabeled host is writable if its label equals the label that is associated with the remote host in its trusted networking database entries. A file or directory that is exported to an unlabeled host is readable only if its label is dominated by the label that is associated with the remote host.

Communications with systems that are running a release of Trusted Solaris software is possible only at a single label. The Trusted Extensions system and the Trusted Solaris system must assign to the other system a template with the unlabeled host type. The unlabeled host types must specify the same single label. As an unlabeled NFS client of a Trusted Solaris server, the label of the client cannot be ADMIN_LOW.

The NFS protocol that is used is independent of the local file system's type. Rather, the protocol depends on the type of the sharing computer's operating system. The file system type that is specified to the mount command or in the vfstab file for remote file systems is always NFS.