route - manually manipulate the routing tables
/usr/etc/route [-nqfF] command [[modifiers] args]
Route is a utility used to manually manipulate the network routing
tables. It normally is not needed, as a system routing table management
daemon such as routed(1M), should tend to this task.
The route utility supports a limited number of general options, but a
rich command language, enabling the user to specify any arbitrary request
that could be delivered via the programmatic interface
-n Bypasses attempts to print host and network names symbolically when
reporting actions. (The process of translating between symbolic
names and numerical equivalents can be quite time consuming, and may
require correct operation of the network; thus it may be expedient to
forgo this, especially when attempting to repair networking
-v (verbose) Print additional details.
-q Suppress all output.
-F Flush all entries, not just gateway entries, usually when restarting
the system. Note that unless at least some of the major non-gateway
routes are immediately restored, the system will not work.
The route utility provides six commands:
add Add a route.
flush Remove all 'gateway' routes. Non-gateway routes are added by
device drivers when the interface is configured, and so should
usually not be removed.
delete Delete a specific route.
change Change aspects of a route (such as its gateway).
get Lookup and display the route for a destination.
monitor Continuously report any changes to the routing information
base, routing lookup misses, or suspected network
The monitor command has the syntax
route [-n] monitor
The flush command has the syntax
route [-n] [-F] flush
If the flush command is specified, route will ``flush'' the routing
tables of all gateway entries. The -F flag flushes all entries are
The other commands have the following syntax:
route [-n] command [-net | -host] destination gateway
where destination is the destination host or network, gateway is the
next-hop intermediary via which packets should be routed. Routes to a
particular host may be distinguished from those to a network by
interpreting the Internet address specified as the destination argument.
destination may be specified with the keyword ``default'' (instead of an
IP address or name) to specify a route to all possible destinations; this
is the route of last resort, used by the system if no better match is
Configuring a static default route is often useful if there is only one
path available to get traffic out of the local subnet. This can be
accomplished easily by adding the route to /etc/config/static-
The optional modifiers net and host force the destination to be
interpreted as a network or a host, respectively. Otherwise, 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.
For example, 128.32 is interpreted as -host 22.214.171.124 ; 128.32.130 is
interpreted as -host 126.96.36.199; -net 128.32 is interpreted as
188.8.131.52; and -net 128.32.130 is interpreted as 184.108.40.206.
If the destination is directly reachable via an interface requiring no
intermediary system to act as a gateway, the -interface modifier should
be specified; the gateway given is the address of this host on the common
network, indicating the interface to be used for transmission.
The optional -netmask qualifier is intended to achieve the effect of an
OSI ESIS redirect with the netmask option, or to manually add subnet
routes with netmasks different from that of the implied network interface
(as would otherwise be communicated using the OSPF or ISIS routing
protocols). One specifies an additional ensuing address parameter (to be
interpreted as a network mask). The implicit network mask generated in
the AF_INET case can be overridden by making sure this option follows the
Routes have associated flags which influence operation of the protocols
when sending to destinations matched by the routes. These flags may be
set (or sometimes cleared) by indicating the following corresponding
-cloning RTF_CLONING - generates a new route on use
-xresolve RTF_XRESOLVE - emit mesg on use (for external lookup)
-iface ~RTF_GATEWAY - destination is directly reachable
-static RTF_STATIC - manually added route
-nostatic ~RTF_STATIC - pretend route added by kernel or daemon
-reject RTF_REJECT - emit an ICMP unreachable when matched
-blackhole RTF_BLACKHOLE - silently discard pkts (during updates)
-proto1 RTF_PROTO1 - set protocol specific routing flag #1
-proto2 RTF_PROTO2 - set protocol specific routing flag #2
-llinfo RTF_LLINFO - validly translates proto addr to link addr
The optional modifiers -rtt, -rttvar, -sendpipe, -recvpipe, -mtu,
-hopcount, -expire, and -ssthresh provide initial values to quantities
maintained in the routing entry by transport level protocols, such as TCP
or TP4. These may be individually locked by preceding each such modifier
to be locked by the -lock meta-modifier, or one can specify that all
ensuing metrics may be locked by the -lockrest meta-modifier.
In a change or add command where the destination and gateway are not
sufficient to specify the route (as in the case where several interfaces
may have the same address), the -ifp or -ifa modifiers may be used to
determine the interface or interface address.
All symbolic names specified for a destination or gateway are looked up
first as a host name using gethostbyname(3). If this lookup fails,
getnetbyname(3) is then used to interpret the name as that of a network.
Route uses a routing socket and the new message types RTM_ADD,
RTM_DELETE, RTM_GET, and RTM_CHANGE. As such, only the super-user may
modify the routing tables.
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(3), 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 flush command 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 which wasn't present in
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.
The first paragraph may have slightly exaggerated routed's abilities.
/etc/config/static-route.options static route configuration file
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