mrinfo(8)

NAME

mrinfo - display configuration info from a multicast router

mrinfo [-d debug_level] [-r retry_count] [-t timeout_count]
       multicast_router

The mrinfo utility attempts to display the configuration in
formation from
the multicast router multicast_router.
The mrinfo utility uses the ASK_NEIGHBORS IGMP message to
the specified multicast router. If this multicast router responds, the
version number and a list of their neighboring multicast router addresses
is part of that response. If the responding router has a recent multi
cast version
number, then mrinfo requests additional information such as
metrics, thresholds, and flags from the multicast router. Once the
specified multicast router responds, the configuration is displayed to
the standard output.
The following options are available:
-d debug_level: Set the debug level. When the debug level is; greater than the
default value of 0, addition debugging messages are; printed.
Regardless of the debug level, an error condition,; will always
write an error message and will cause mrinfo to ter; minate. Nonzero debug levels have the following effects:; level 1
packet warnings are printed to stderr.
level 2: all level 1 messages plus notifications down; networks are
printed to stderr.
level 3: all level 2 messages plus notifications of; all packet
timeouts are printed to stderr.
-r retry_count: Set the neighbor query retry limit. Default is 3; retries.
-t timeout_count: Set the number of seconds to wait for a neighbor; query reply.
Default timeout is 4 seconds.

$ mrinfo mbone.phony.dom.net 127.148.176.10 (mbone.phony.dom.net) [version 3.3]:: 127.148.176.10 -> 0.0.0.0 (?) [1/1/querier]
127.148.176.10 -> 127.0.8.4 (mbone2.phony.dom.net); [1/45/tunnel]
127.148.176.10 -> 105.1.41.9 (momoney.com) [1/32/tun; nel/down]
127.148.176.10 -> 143.192.152.119 (mbone.dipu.edu); [1/32/tunnel]
For each neighbor of the queried multicast router, the IP of
the queried router is displayed, followed by the IP and name of the
neighbor. In square brackets the metric (cost of connection), the thresh
old (multicast ttl) is displayed. If the queried multicast router has a
newer version number, the type (tunnel, srcrt) and status (disabled, down)
of the connection is displayed.

The mrinfo utility must be run as root.