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.\" 30.Dd March 25, 2007 31.Dt EDSC 4 32.Os 33.Sh NAME 34.Nm edsc 35.Nd Ethernet discard network interface 36.Sh SYNOPSIS 37.Cd "device edsc" 38.Sh DESCRIPTION 39The 40.Nm 41interface is a software discard mechanism which may be 42used for performance analysis and software testing. 43It imitates an Ethernet device, which 44allows for its use in conjunction with such drivers as 45.Xr if_bridge 4 46and 47.Xr vlan 4 . 48.Pp 49As with other network interfaces, an 50.Nm 51interface must have network addresses assigned for each address family 52with which it is to be used. 53These addresses may be set or changed with the 54.Dv SIOCSIFADDR 55.Xr ioctl 2 56or 57.Xr ifconfig 8 58utility. 59.Pp 60Each 61.Nm 62interface is created at runtime using interface cloning. 63This is most easily done with the 64.Xr ifconfig 8 65.Cm create 66command or using the 67.Va cloned_interfaces 68variable in 69.Xr rc.conf 5 . 70.Sh SEE ALSO 71.Xr ioctl 2 , 72.Xr arp 4 , 73.Xr if_bridge 4 , 74.Xr inet 4 , 75.Xr intro 4 , 76.Xr vlan 4 , 77.Xr rc.conf 5 , 78.Xr arp 8 , 79.Xr ifconfig 8 80.Sh HISTORY 81The 82.Nm 83device was derived from the 84.Xr disc 4 85device and first appeared in 86.Fx 6.3 . 87This manpage was adapted from 88.Xr disc 4 . 89.Sh CAVEATS 90Since outgoing packets are just discarded by 91.Nm , 92ARP requests stay unreplied. 93Consequently, an IP packet cannot be sent via 94.Nm 95until a static 96.Xr arp 4 97entry is created for its next hop using 98.Xr arp 8 . 99.Pp 100Initially an 101.Nm 102interface has a zero link level address. 103It can be changed with 104.Xr ifconfig 8 105.Cm lladdr 106if needed. 107