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