SunOS man pages : in.routed (1)
Maintenance Commands in.routed(1M)
NAME
in.routed, routed - network routing daemon
SYNOPSIS
/usr/sbin/in.routed [ -s ] [ -q ] [ -t ] [ -g ] [ -S ]
[ -v ] [ logfile ]
DESCRIPTION
in.routed is invoked at boot time to manage the network
routing tables. The routing daemon uses a variant of the
Xerox NS Routing Information Protocol in maintaining up-to-
date kernel routing table entries.
In normal operation, in.routed listens on udp(7P) socket 520
(decimal) 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.routed is started, it uses the SIOCGIFCONF ioctl(2)
to find those directly connected 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.routed then transmits a request packet on each interface
(using a broadcast packet if the interface supports it) and
enters a loop, listening for request and response packets
from other hosts.
When a request packet is received, in.routed formulates a
reply based on the information maintained in its internal
tables. The response packet contains a list of known routes,
each marked with a "hop count" metric (a count of 16, or
greater, is considered "infinite"). The metric associated
with each route returned, provides a metric relative to the
sender.
request packets received by in.routed are used to update the
routing tables if one of the following conditions is satis-
fied:
o No routing table entry exists for the destination net-
work or host, and the metric indicates the destination
is "reachable" (that is, the hop count is not infin-
ite).
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 des-
tination are being routed.
o The existing entry in the routing table has not been
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Maintenance Commands in.routed(1M)
updated for some 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; the metric of the new route is compared
against the one stored in the table to decide this.
When an update is applied, in.routed records the change in
its internal tables and generates a response packet to all
directly connected hosts and networks. in.routed waits a
short period of time (no more than 30 seconds) before modi-
fying the kernel's routing tables to allow possible unstable
situations to settle.
In addition to processing incoming packets, in.routed 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 con-
nected hosts and networks.
In addition to the facilities described above, in.routed
supports the notion of "distant" passive and active gate-
ways. When in.routed is started up, it reads the file gate-
ways to find gateways which may not be identified using the
SIOCGIFCONFioctl. Gateways specified in this manner should
be marked passive if they are not expected to exchange
routing information, while gateways marked active should be
willing to exchange routing information (that is, they
should have a in.routed process running on the machine).
Routes through passive gateways are installed in the
kernel's routing tables once upon startup. They may change,
depending upon routing information they receive from other
gateways. Information regarding their existence is not
included in any routing information transmitted. Active
gateways are treated equally to network interfaces. Routing
information is distributed to the gateway, and if no routing
information is received for a period of time, the associated
route is deleted.
The gateways is comprised of a series of lines, each in the
following format:
< net | host > filename1 gateway filename2 metric value < passive | active >
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Maintenance Commands in.routed(1M)
The net or host keyword indicates if the route is to a net-
work or specific host.
filename1 is the name of the destination network or host.
This may be a symbolic name located in networks or hosts, or
an Internet address specified in "dot" notation; see
inet(3SOCKET).
filename2 is the name or address of the gateway to which
messages should be forwarded.
value is a metric indicating the hop count to the destina-
tion host or network.
The keyword passive or active indicates if the gateway
should be treated as passive or active (as described above).
OPTIONS
-g Is used on internetwork routers to offer a route to
the ``default'' destination. This is typically used on
a gateway to the Internet, or on a gateway that uses
another routing protocol whose routes are not reported
to other local routers.
-q Is the opposite of the -s option.
-s Forces in.routed to supply routing information whether
it is acting as an internetwork router or not.
-S If in.routed is not acting as an internetwork router
it will, instead of entering the whole routing table
in the kernel, only enter a default route for each
internetwork router. This reduces the the memory
requirements without losing any routing reliability.
-t All packets sent or received are printed on standard
output. In addition, in.routed will not divorce itself
from the controlling terminal so that interrupts from
the keyboard will kill the process. Any other argument
supplied is interpreted as the name of the file in
which in.routed's actions should be logged. This log
contains information about any changes to the routing
tables and a history of recent messages sent and
received which are related to the changed route.
-v Allows a logfile (whose name must be supplied) to be
created showing the changes made to the routing tables
with a timestamp.
FILES
/etc/gateways
for distant gateways
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Maintenance Commands in.routed(1M)
/etc/networks
associations of Internet Protocol network numbers with
network names
/etc/hosts
Internet host table
ATTRIBUTES
See attributes(5) for descriptions of the following attri-
butes:
____________________________________________________________
| ATTRIBUTE TYPE | ATTRIBUTE VALUE |
|_____________________________|_____________________________|
| Availability | SUNWcsu |
|_____________________________|_____________________________|
SEE ALSO
route(1M), ioctl(2), inet(3SOCKET), attributes(5), inet(7P),
udp(7P)
NOTES
The kernel's routing tables may not correspond to those of
in.routed 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.routed should listen to intelligent interfaces, such as
an IMP, and to error protocols, such as ICMP, to gather more
information.
in.routed initially obtains a routing table by examining the
interfaces configured on a machine and the gateways file.
It then sends a request on all directly connected networks
for more routing information. in.routed does not recognize
or use any routing information already established on the
machine prior to startup. With the exception of interface
changes, in.routed 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.routed is running. Rather,
shut down in.routed, make the changes required, and then
restart in.routed.
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