1.\" Copyright (c) 1983, 1991, 1993 2.\" The Regents of the University of California. All rights reserved. 3.\" 4.\" Redistribution and use in source and binary forms, with or without 5.\" modification, are permitted provided that the following conditions 6.\" are met: 7.\" 1. Redistributions of source code must retain the above copyright 8.\" notice, this list of conditions and the following disclaimer. 9.\" 2. Redistributions in binary form must reproduce the above copyright 10.\" notice, this list of conditions and the following disclaimer in the 11.\" documentation and/or other materials provided with the distribution. 12.\" 3. All advertising materials mentioning features or use of this software 13.\" must display the following acknowledgement: 14.\" This product includes software developed by the University of 15.\" California, Berkeley and its contributors. 16.\" 4. Neither the name of the University nor the names of its contributors 17.\" may be used to endorse or promote products derived from this software 18.\" without specific prior written permission. 19.\" 20.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 21.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 22.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 23.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 24.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 25.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 26.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 27.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 28.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 29.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 30.\" SUCH DAMAGE. 31.\" 32.\" From: @(#)lo.4 8.1 (Berkeley) 6/5/93 33.\" $FreeBSD$ 34.\" 35.Dd March 25, 2007 36.Dt EDSC 4 37.Os 38.Sh NAME 39.Nm edsc 40.Nd Ethernet discard network interface 41.Sh SYNOPSIS 42.Cd "device edsc" 43.Sh DESCRIPTION 44The 45.Nm 46interface is a software discard mechanism which may be 47used for performance analysis and software testing. 48It imitates an Ethernet device, which 49allows for its use in conjunction with such drivers as 50.Xr if_bridge 4 51and 52.Xr vlan 4 . 53.Pp 54As with other network interfaces, an 55.Nm 56interface must have network addresses assigned for each address family 57with which it is to be used. 58These addresses may be set or changed with the 59.Dv SIOCSIFADDR 60.Xr ioctl 2 61or 62.Xr ifconfig 8 63utility. 64.Pp 65Each 66.Nm 67interface is created at runtime using interface cloning. 68This is most easily done with the 69.Xr ifconfig 8 70.Cm create 71command or using the 72.Va cloned_interfaces 73variable in 74.Xr rc.conf 5 . 75.Sh SEE ALSO 76.Xr ioctl 2 , 77.Xr arp 4 , 78.Xr if_bridge 4 , 79.Xr inet 4 , 80.Xr intro 4 , 81.Xr vlan 4 , 82.Xr rc.conf 5 , 83.Xr arp 8 , 84.Xr ifconfig 8 85.Sh HISTORY 86The 87.Nm 88device was derived from the 89.Xr disc 4 90device and first appeared in 91.Fx 6.3 . 92This manpage was adapted from 93.Xr disc 4 . 94.Sh CAVEATS 95Since outgoing packets are just discarded by 96.Nm , 97ARP requests stay unreplied. 98Consequently, an IP packet cannot be sent via 99.Nm 100until a static 101.Xr arp 4 102entry is created for its next hop using 103.Xr arp 8 . 104.Pp 105Initially an 106.Nm 107interface has a zero link level address. 108It can be changed with 109.Xr ifconfig 8 110.Cm lladdr 111if needed. 112