in.ripngd(1M)
NAME
in.ripngd - network routing daemon for IPv6
SYNOPSIS
/usr/sbin/in.ripngd [-s] [-q] [-t] [-p n] [-P] [-v ] [log-
file]
DESCRIPTION
in.ripngd is the IPv6 equivalent of in.routed(1M).
It is invoked at boot time to manage the network routing
tables. The routing daemon uses the Routing Information Pro-
tocol for IPv6.
In normal operation, in.ripngd listens on the udp(7P) 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.
Whenin.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 desti-
nation 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.
OPTIONS
in.ripngd supports the following options:
-q Do not supply routing information.
-s Force in.ripngd to supply routing information
whether it is acting as an internetwork router or
not.
-p n Send and receive the routing packets from other
routers using the UDP port number n.
-P Do not use poison reverse.
-t Print all packets sent or received to standard
output. in.ripngd will not divorce itself from
the controlling terminal. Accordingly, inter-
rupts
from the keyboard will kill the process.
-v Print all changes made to the routing tables to
standard output with a timestamp.
Any other argument supplied 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 versus being sent to standard
output.
ATTRIBUTES
See attributes(5)
for descriptions of the following attributes:
____________________________________________________________
| ATTRIBUTE TYPE | ATTRIBUTE VALUE |
|_____________________________|_____________________________|
| Availability | SUNWroute |
|_____________________________|_____________________________|
SEE ALSO
in.routed(1M), ioctl(2), attributes(5), udp(7P)
Malkin, G., Minnear, R., RFC 2080, RIPng for IPv6, January
1997.
NOTES
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 functional-
ity of in.routed(1M). 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 informa-
tion. in.ripngd does not recognize or use any routing infor-
mation 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 way of the route(1M) 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.
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