IN.RIPNGD(8) Maintenance Procedures IN.RIPNGD(8)


in.ripngd - network routing daemon for IPv6


/usr/sbin/in.ripngd [-s] [-q] [-t] [-p n] [-P] [-v ]


in.ripngd is the IPv6 equivalent of in.routed(8). It is invoked at boot
time to manage the network routing tables. The routing daemon uses the
Routing Information Protocol for IPv6.

in.ripngd is managed by the service management facility (SMF), by means
of the service identifier:


In normal operation, in.ripngd listens on the udp(4P) socket port 521 for
routing information packets. If the host is an internetwork router, it
periodically supplies copies of its routing tables to any directly
connected hosts and networks.

When in.ripngd is started, it uses the SIOCGLIFCONF ioctl(2) to find
those directly connected IPv6 interfaces configured into the system and
marked "up"; the software loopback interface is ignored. If multiple
interfaces are present, it is assumed the host will forward packets
between networks. in.ripngd then multicasts a request packet on each
IPv6 interface and enters a loop, listening for request and response
packets from other hosts.

When a request packet is received, in.ripngd formulates a reply based on
the information maintained in its internal tables. The response packet
contains a list of known routes. With each route is a number specifying
the number of bits in the prefix. The prefix is the number of bits in the
high order part of an address that indicate the subnet or network that
the route describes. Each route reported also has a "hop count" metric. A
count of 16 or greater is considered "infinity." The metric associated
with each route returned provides a metric relative to the sender.

The request packets received by in.ripngd are used to update the routing
tables if one of the following conditions is satisfied:

o No routing table entry exists for the destination network or
host, and the metric indicates the destination is "reachable",
that is, the hop count is not infinite.

o The source host of the packet is the same as the router in the
existing routing table entry. That is, updated information is
being received from the very internetwork router through which
packets for the destination are being routed.

o The existing entry in the routing table has not been updated
for a period of time, defined to be 90 seconds, and the route
is at least as cost-effective as the current route.

o The new route describes a shorter route to the destination
than the one currently stored in the routing tables; this is
determined by comparing the metric of the new route against
the one stored in the table.

When an update is applied, in.ripngd records the change in its internal
tables and generates a response packet to all directly connected hosts
and networks. To allow possible unstable situations to settle, in.ripngd
waits a short period of time (no more than 30 seconds) before modifying
the kernel's routing tables.

In addition to processing incoming packets, in.ripngd also periodically
checks the routing table entries. If an entry has not been updated for 3
minutes, the entry's metric is set to infinity and marked for deletion.
Deletions are delayed an additional 60 seconds to insure the invalidation
is propagated throughout the internet.

Hosts acting as internetwork routers gratuitously supply their routing
tables every 30 seconds to all directly connected hosts and networks.


in.ripngd supports the options listed below. Listed with the options are
the equivalent SMF property values. These are set for the ripng:default
service with a command of the form:

# routeadm -m ripng:default key=value

-p n
Send and receive the routing packets from other routers using the
UDP port number n. Use of this option is equivalent to setting
the udp_port property.

Do not use poison reverse. Use of this option is equivalent to
setting the poison_reverse property to false.

Do not supply routing information. Use of this option is
equivalent to setting the quiet_mode property to true.

Force in.ripngd to supply routing information whether it is
acting as an internetwork router or not. Use of this option is
equivalent to setting the supply_routes property to true.

Print all packets sent or received to standard output. in.ripngd
will not divorce itself from the controlling terminal.
Accordingly, interrupts from the keyboard will kill the process.
Not supported by the ripng service.

Print all changes made to the routing tables to standard output
with a timestamp. Use of this option is equivalent to setting the
verbose property to true.

Any other argument supplied to this option is interpreted as the
name of the file in which the actions of in.ripngd, as specified
by this option or by -t, should be logged instead of being sent
to standard output.

The logfile can be specified for the ripng service by means of
the log_file property.


ioctl(2), udp(4P), attributes(7), smf(7), in.routed(8), routeadm(8),

G. Malkin, R. Minnear, RFC 2080, RIPng for IPv6, January 1997.


The kernel's routing tables may not correspond to those of in.ripngd for
short periods of time while processes that utilize existing routes exit;
the only remedy for this is to place the routing process in the kernel.

in.ripngd currently does not support all of the functionality of
in.routed(8). Future releases may support more if appropriate.

in.ripngd initially obtains a routing table by examining the interfaces
configured on a machine. It then sends a request on all directly
connected networks for more routing information. in.ripngd does not
recognize or use any routing information already established on the
machine prior to startup. With the exception of interface changes,
in.ripngd does not see any routing table changes that have been done by
other programs on the machine, for example, routes added, deleted or
flushed by means of the route(8) command. Therefore, these types of
changes should not be done while in.ripngd is running. Rather, shut down
in.ripngd, make the changes required, and then restart in.ripngd.

January 26, 2007 IN.RIPNGD(8)