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IFMCSTAT(8)		    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  in-
		   formation.

       -M core	   extracts  values  associated	 with  the  name list from the
		   specified 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
       interface.

       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
       multicast  group	memberships are	present	on those interfaces.  The out-
       put may also be slightly	different, as the kernel data  structures  are
       being traversed 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 run-
       ning kernel.

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

FreeBSD	14.3			 May 27, 2009			   IFMCSTAT(8)

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