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.\" Copyright (c) 2008 George V. Neville-Neil
.\" All rights reserved.
.\"
.\" Redistribution and use in source and binary forms, with or without
.\" modification, are permitted provided that the following conditions
.\" are met:
.\" 1. Redistributions of source code must retain the above copyright
.\" notice, this list of conditions and the following disclaimer.
.\" 2. Redistributions in binary form must reproduce the above copyright
.\" notice, this list of conditions and the following disclaimer in the
.\" documentation and/or other materials provided with the distribution.
.\"
.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
.\" ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
.\" SUCH DAMAGE.
.\"
.\" $FreeBSD$
.\"
.Dd July 9, 2008
.Dt MCGRAB 1
.Os
.Sh NAME
.Nm mcgrab
.Nd "multicast filter overload test"
.Sh SYNOPSIS
.Nm
.Op Fl i Ar interface
.Op Fl g Ar group
.Op Fl n Ar number
.Sh DESCRIPTION
The
.Nm
command implements a multicast test which grabs and holds
N multicast addresses.
The purpose of the test is to see what
happens when a network interface is no longer able to filter
multicasts in hardware and has to switch to promiscuous or
multicast promiscuous mode.
A successful test does not have any
result, but an unsuccessful test will have deleterious side effects.
Packet size in bytes.
The options are as follows:
.Bl -tag -width ".Fl i Ar interface"
.It Fl i Ar interface
Network interface, which can be found with
.Xr ifconfig 8 .
.It Fl g Ar group
Multicast group.
.It Fl n Ar number
Number of groups to join.
.El
.Sh EXAMPLES
The following is an example of a typical usage
of the
.Nm
command:
.Pp
.Dl "mcgrab -i em0 -g 239.255.255.1 -n 1024"
.Sh SEE ALSO
.Xr mctest 1 ,
.Xr netstat 1 ,
.Xr nanosleep 2 ,
.Xr ifconfig 8
.Sh HISTORY
The
.Nm
program first appeared in
.Fx 7.0 .
.Sh AUTHORS
This
manual page was written by
.An George V. Neville-Neil Aq gnn@FreeBSD.org .
.Sh BUGS
Should be reported to the author or to
.Aq net@FreeBSD.org .
|
