ETC PF-NFS local subnetwork mask
A subnet is a self-contained region within a larger net. It
can handle network traffic that never reaches the larger net. PC's on a
subnet need use only the final part of their Internet addresses,
the first being common to all said addresses. The subnet mask removes
the common
part, leaving only the subnet address components. PCNFS requests
the correct subnet mask from the network.
(Bugs in the support for
subnet in the previous version (3.0, with SunOS 3 and 4) prevented it
from being used initially, but this has been repaired).