'\"macro stdmacro
.if n .pH g4.netmasks @(#)netmasks	40.4 of 10/10/89
.\" Copyright 1989 AT&T
.\" @(#)netmasks.4 1.2 89/07/14 SMI;
'\" macro stdmacro
.\" Copyright (c) 1988 Sun Microsystems, Inc. - All Rights Reserved.
.\"
.nr X
.if \nX=0 .ds x} netmasks 4 "TCP/IP" "\&"
.if \nX=1 .ds x} netmasks 4 "TCP/IP"
.if \nX=2 .ds x} netmasks 4 "" "\&"
.if \nX=3 .ds x} netmasks "" "" "\&"
.TH \*(x}
.SH NAME
\f4netmasks\f1 \- network mask data base
.SH DESCRIPTION
.PP
The
\f4netmasks\f1
file contains network masks used to implement
.SM IP
standard subnetting.
For each network that is subnetted,
a single line should exist
in this file with the network number, any number of
.SM SPACE
or
.SM TAB
characters,
and the network mask to use on that network.
Network numbers and masks may be specified
in the conventional
.SM IP
\f1`\f4.\f1'
notation (like
.SM IP
host addresses, but with zeroes for the host
part). 
For example,
.IP
\f4128.32.0.0 255.255.255.0
.PP
can be used to specify that the Class B
network 128.32.0.0 should have
eight bits of subnet field and eight
bits of host field, in addition to
the standard sixteen bits in the network field.
.SH FILES
.PD 0
.TP 20
\f4/etc/netmasks\f1
.PD
.SH "SEE ALSO"
\f4ifconfig\fP(1M)
.PP
Postel, Jon, and Mogul, Jeff,
.IR "Internet Standard Subnetting Procedure" ,
.SM RFC
950,
Network Information Center,
.SM SRI
International, Menlo Park, Calif.,
August 1985.
