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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 informa-
		 tion.

     -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  multicast
     group  memberships are present on those interfaces.  The output 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 re-
     quires super-user privilege if used to inspect a running kernel.

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

FreeBSD ports 15.quarterly	  May 27, 2009			     IFMCSTAT(8)

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