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.Dd March 25, 2007 29.Dt EDSC 4 30.Os 31.Sh NAME 32.Nm edsc 33.Nd Ethernet discard network interface 34.Sh SYNOPSIS 35.Cd "device edsc" 36.Sh DESCRIPTION 37The 38.Nm 39interface is a software discard mechanism which may be 40used for performance analysis and software testing. 41It imitates an Ethernet device, which 42allows for its use in conjunction with such drivers as 43.Xr if_bridge 4 44and 45.Xr vlan 4 . 46.Pp 47As with other network interfaces, an 48.Nm 49interface must have network addresses assigned for each address family 50with which it is to be used. 51These addresses may be set or changed with the 52.Dv SIOCSIFADDR 53.Xr ioctl 2 54or 55.Xr ifconfig 8 56utility. 57.Pp 58Each 59.Nm 60interface is created at runtime using interface cloning. 61This is most easily done with the 62.Xr ifconfig 8 63.Cm create 64command or using the 65.Va cloned_interfaces 66variable in 67.Xr rc.conf 5 . 68.Sh SEE ALSO 69.Xr ioctl 2 , 70.Xr arp 4 , 71.Xr if_bridge 4 , 72.Xr inet 4 , 73.Xr intro 4 , 74.Xr vlan 4 , 75.Xr rc.conf 5 , 76.Xr arp 8 , 77.Xr ifconfig 8 78.Sh HISTORY 79The 80.Nm 81device was derived from the 82.Xr disc 4 83device and first appeared in 84.Fx 6.3 . 85This manpage was adapted from 86.Xr disc 4 . 87.Sh CAVEATS 88Since outgoing packets are just discarded by 89.Nm , 90ARP requests stay unreplied. 91Consequently, an IP packet cannot be sent via 92.Nm 93until a static 94.Xr arp 4 95entry is created for its next hop using 96.Xr arp 8 . 97.Pp 98Initially an 99.Nm 100interface has a zero link level address. 101It can be changed with 102.Xr ifconfig 8 103.Cm lladdr 104if needed. 105