1.\" Copyright (c) 2008 George V. Neville-Neil 2.\" 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.\" 13.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 14.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 15.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 16.\" ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 17.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 18.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 19.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 20.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 21.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 22.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 23.\" SUCH DAMAGE. 24.\" 25.\" $FreeBSD$ 26.\" 27.Dd July 9, 2008 28.Dt MCGRAB 1 29.Os 30.Sh NAME 31.Nm mcgrab 32.Nd "multicast filter overload test" 33.Sh SYNOPSIS 34.Nm 35.Op Fl i Ar interface 36.Op Fl g Ar group 37.Op Fl n Ar number 38.Sh DESCRIPTION 39The 40.Nm 41command implements a multicast test which grabs and holds 42N multicast addresses. 43The purpose of the test is to see what 44happens when a network interface is no longer able to filter 45multicasts in hardware and has to switch to promiscuous or 46multicast promiscuous mode. 47A successful test does not have any 48result, but an unsuccessful test will have deleterious side effects. 49Packet size in bytes. 50The options are as follows: 51.Bl -tag -width ".Fl i Ar interface" 52.It Fl i Ar interface 53Network interface, which can be found with 54.Xr ifconfig 8 . 55.It Fl g Ar group 56Multicast group. 57.It Fl n Ar number 58Number of groups to join. 59.El 60.Sh EXAMPLES 61The following is an example of a typical usage 62of the 63.Nm 64command: 65.Pp 66.Dl "mcgrab -i em0 -g 239.255.255.1 -n 1024" 67.Sh SEE ALSO 68.Xr mctest 1 , 69.Xr netstat 1 , 70.Xr nanosleep 2 , 71.Xr ifconfig 8 72.Sh HISTORY 73The 74.Nm 75program first appeared in 76.Fx 7.0 . 77.Sh AUTHORS 78This 79manual page was written by 80.An George V. Neville-Neil Aq Mt gnn@FreeBSD.org . 81.Sh BUGS 82Should be reported to the author or to 83.Aq Mt net@FreeBSD.org . 84