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IFMCSTAT(8)		FreeBSD	System Manager's Manual		   IFMCSTAT(8)

NAME
     ifmcstat -- dump multicast	group management statistics per	interface

SYNOPSIS
     ifmcstat [-i interface] [-f address-family] [-v] [-K] [-M core]
	      [-N system]

DESCRIPTION
     The ifmcstat command dumps	multicast group	information from the kernel.

     The following options are supported:

     -i	interface
		 specifies the interface to be displayed.

     -f	address-family
		 specifies the address family to be displayed; inet, inet6 and
		 link are supported.

     -v		 specifies that	link-layer memberships should be printed; they
		 are suppressed	by default.  It	may not	be specified for -f
		 link.	Source lists for each group will also be printed.

		 If specified twice, and kvm(3)	is in use, the control plane
		 timers	for each interface and the source list counters	for
		 each group will also be printed.

     The following options are only available if ifmcstat has been built with
     support for kvm(3):

     -K		 attempts to use kvm(3)	to retrieve the	multicast group	infor-
		 mation.

     -M	core	 extracts values associated with the name list from the	speci-
		 fied core, instead of the default /dev/kmem.

     -N	system	 extracts the name list	from the specified kernel instead of
		 the default, which is the kernel image	the system has booted
		 from.

IMPLEMENTATION NOTES
     ifmcstat will always print	the embedded scope IDs of IPv6 multicast group
     memberships.  This	is because memberships are always scoped to an inter-
     face.

     When run with the -v option, ifmcstat may print multicast MAC addresses
     twice if they are referenced by a layer 3 protocol.

     When run with kvm(3) support, the names of	all interfaces configured in
     the system	will be	printed	in the first column of output, even if no mul-
     ticast group memberships are present on those interfaces.	The output may
     also be slightly different, as the	kernel data structures are being tra-
     versed with minimal post-processing of the	output.

     When built	without	kvm(3) support,	the information	displayed by ifmcstat
     is	more limited.  This support is recommended for debugging purposes.  It
     requires super-user privilege if used to inspect a	running	kernel.

SEE ALSO
     netstat(1), getifaddrs(3),	getifmaddrs(3),	kvm(3)

FreeBSD	9.3			 May 27, 2009			   FreeBSD 9.3

NAME | SYNOPSIS | DESCRIPTION | IMPLEMENTATION NOTES | SEE ALSO

Want to link to this manual page? Use this URL:
<http://www.freebsd.org/cgi/man.cgi?query=ifmcstat&manpath=FreeBSD+9.3-RELEASE>

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