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.\" Copyright (c) 1983, 1991, 1993
.\" The Regents of the University of California. All rights reserved.
.\"
.\" Redistribution and use in source and binary forms, with or without
.\" modification, are permitted provided that the following conditions
.\" are met:
.\" 1. Redistributions of source code must retain the above copyright
.\" notice, this list of conditions and the following disclaimer.
.\" 2. Redistributions in binary form must reproduce the above copyright
.\" notice, this list of conditions and the following disclaimer in the
.\" documentation and/or other materials provided with the distribution.
.\" 3. All advertising materials mentioning features or use of this software
.\" must display the following acknowledgement:
.\" This product includes software developed by the University of
.\" California, Berkeley and its contributors.
.\" 4. Neither the name of the University nor the names of its contributors
.\" may be used to endorse or promote products derived from this software
.\" without specific prior written permission.
.\"
.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
.\" SUCH DAMAGE.
.\"
.\" From: @(#)lo.4 8.1 (Berkeley) 6/5/93
.\" $FreeBSD$
.\"
.Dd March 25, 2007
.Dt EDSC 4
.Os
.Sh NAME
.Nm edsc
.Nd Ethernet discard network interface
.Sh SYNOPSIS
.Cd "device edsc"
.Sh DESCRIPTION
The
.Nm
interface is a software discard mechanism which may be
used for performance analysis and software testing.
It imitates an Ethernet device, which
allows for its use in conjunction with such drivers as
.Xr if_bridge 4
and
.Xr vlan 4 .
.Pp
As with other network interfaces, an
.Nm
interface must have network addresses assigned for each address family
with which it is to be used.
These addresses may be set or changed with the
.Dv SIOCSIFADDR
.Xr ioctl 2
or
.Xr ifconfig 8
utility.
.Pp
Each
.Nm
interface is created at runtime using interface cloning.
This is most easily done with the
.Xr ifconfig 8
.Cm create
command or using the
.Va cloned_interfaces
variable in
.Xr rc.conf 5 .
.Sh SEE ALSO
.Xr ioctl 2 ,
.Xr arp 4 ,
.Xr if_bridge 4 ,
.Xr inet 4 ,
.Xr intro 4 ,
.Xr vlan 4 ,
.Xr rc.conf 5 ,
.Xr arp 8 ,
.Xr ifconfig 8
.Sh HISTORY
The
.Nm
device was derived from the
.Xr disc 4
device and first appeared in
.Fx 6.3 .
This manpage was adapted from
.Xr disc 4 .
.Sh CAVEATS
Since outgoing packets are just discarded by
.Nm ,
ARP requests stay unreplied.
Consequently, an IP packet cannot be sent via
.Nm
until a static
.Xr arp 4
entry is created for its next hop using
.Xr arp 8 .
.Pp
Initially an
.Nm
interface has a zero link level address.
It can be changed with
.Xr ifconfig 8
.Cm lladdr
if needed.
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