10.2;route, revision 2.0, 89/03/31
route - manually manipulate the routing tables
usage: route [-f] [-n] [command-args]
DESCRIPTION
route is a program used to manually manipulate the network routing
tables. It normally is not needed, as the system routing table
management daemon, routed, should tend to this task.
route accepts three commands: add, to add a route; addp, to add a
priority route; and delete, to delete a route.
The addp command adds a priority route. The TCP/IP server process will
use priority routes before default routes or routes established by
routed. A route added with addp will appear first in the gateway table
(displayed with the Aegis command netstat -r). You can only add priority
routes with addp. Routes added manually by route cannot be deleted by
routed.
COMMAND SYNTAX
All commands have the following syntax:
/etc/route command [ net | host ] destination gateway [ metric ]
where destination is the destination host or network, gateway is the
next-hop gateway to which packets should be addressed, and metric is a
count indicating the number of hops to the destination. The metric is
required for add and addp commands; it must be zero if the destination is
on a directly-attached network, and nonzero if the route utilizes one or
more gateways. If adding a route with metric 0, the gateway given is the
address of this host on the common network, indicating the interface to
be used for transmission.
Routes to a particular host are distinguished from those to a network by
interpreting the Internet address associated with destination. The
optional keywords net and host force the destination to be interpreted as
a network or a host, respectively. If the destination has a "local
address part" of INADDR_ANY, or if the destination is the symbolic name
of a network, then the route is assumed to be to a network; otherwise, it
is presumed to be a route to a host.
If the route is to a destination connected through a gateway, the metric
should be greater than 0. All symbolic names specified for a destination
or gateway are looked up first as a host name using gethostbyname. If
this lookup fails, getnetbyname is then used to interpret the name as
that of a network.
You can add a default route as follows:
/etc/route add default gateway_name [non-zero metric]
TCP/IP software will use the default route when other routes occuring
earlier in the routing table have failed, or when there are no other
possible routes.
route uses a raw socket and the SIOCADDRT and SIOCDELRT ioctl's(2) to do
its work. As such, only the super-user may modify the routing tables.
OPTIONS
-f "Flush" the routing tables of all gateway entries. Using this
option in conjunction with one of the commands described above
flushes the tables prior to the command's application.
-n Suppress printing symbolic host and network names when reporting
actions.
DIAGNOSTICS
add [ host | network ] %s: gateway %s flags %x
The specified route is being added to the tables. The values printed are
from the routing table entry supplied in the ioctl(2) call. If the
gateway address used was not the primary address of the gateway (the
first one returned by gethostbyname), the
gateway address is printed numerically as well as symbolically.
delete [ host | network ] %s: gateway %s flags %x
As above, but when deleting an entry.
%s %s done
When the -f flag is specified, each routing table entry deleted is
indicated with a message of this form.
Network is unreachable
An attempt to add a route failed because the gateway listed was not on a
directly-connected network. The next-hop gateway must be given.
not in table
A delete operation was attempted for an entry that wasn't present in the
tables.
routing table overflow
An add operation was attempted, but the system was low on resources and
was unable to allocate memory to create the new entry.
SEE ALSO
routed;
Configuring and Managing TCP/IP.