| ROUTE(8) | System Manager's Manual | ROUTE(8) | 
route —
| route | [ -dfLnqSsTtv] command
      [[modifiers] args] | 
route is a utility used to manually manipulate the
  network routing tables. Except for setting up the default route, it is
  normally not needed, as a system routing table management daemon such as
  routed(8), should tend to this
  task.
route can be used to modify nearly any
    aspect of the routing policy, except packet forwarding, which can be
    manipulated through the
    sysctl(8) command.
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 discussed in
    route(4).
-d-fflush). If used in
      conjunction with the add,
      change, delete or
      get commands, route
      removes the routes before performing the command.-L-n-q-S-sget command
      except for the actual gateway that will be used. How the gateway is
      printed depends on the type of route being looked up.-T-t-vThe route utility provides several
    commands:
addflushflushalldeletechangegetshowmonitorThe monitor command has the syntax
route
  [-n] monitor
  [-c count]If count is specified,
    route exits after receiving
    count routing messages.
The flush command has the syntax
route
  [-n] flush
  [family]If the flush command is specified,
    route will ``flush'' the routing tables of all
    gateway entries. When the address family is specified by any of the
    -atalk, -inet,
    -inet6, or -mpls modifiers,
    only routes having destinations with addresses in the delineated family will
    be manipulated.
The other commands have the following syntax:
route
  [-n] command
  [-net |
  -host] destination gatewaywhere destination is the destination host or
    network, and 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. 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. Optionally, the destination can also
    be specified in the net/bits
    format.
For example, 128.32 is interpreted as
    -host 128.0.0.32;
    128.32.130 is interpreted as
    -host 128.32.0.130;
    -net 128.32 is interpreted
    as 128.32.0.0; and -net
    128.32.130 is interpreted as
    128.32.130.0.
The keyword default can be used as the
    destination to set up a default route to a smart
    gateway. If no other routes match, this default route
    will be used as a last resort.
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 modifiers -atalk, and
    -link specify that all subsequent addresses are in
    the AppleTalk address family, or are specified as link-level addresses in
    the form described in
    link_addr(3), and the names
    must be numeric specifications rather than symbolic names.
The optional modifier -tag specifies an
    address associated with the route. How the address is used is specific to
    the address family of the destination and the interface used to forward the
    packet. Currently route tags are consumed only by the
    mpls(4) stack; therefore
    route assumes that the subsequent addresses are in
    the MPLS address family. See
    mpls(4) for examples of setting
    routes involving MPLS.
The optional -netmask qualifier is
    intended to achieve the effect of an 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 destination parameter.
    -prefixlen is also available for similar purpose, in
    IPv4 and IPv6 case.
Routes have associated flags which influence operation of the protocols when sending to destinations matched by the routes. These flags are displayed using the following ID characters in the routing display and may be set (or sometimes cleared) by indicating the following corresponding modifiers:
| ID | Modifier | Flag Bit | Description | 
| 1 | -proto1 | RTF_PROTO1 | set protocol specific flag #1 | 
| 2 | -proto2 | RTF_PROTO2 | set protocol specific flag #2 | 
| B | -blackhole | RTF_BLACKHOLE | discard pkts (during updates) | 
|   | -noblackhole | ~RTF_BLACKHOLE | clear blackhole flag | 
| b | RTF_BROADCAST | route represents a broadcast address | |
| C | -cloning | RTF_CLONING | (deprecated) same as -connected | 
|   | -nocloning | ~RTF_CLONING | (deprecated) same as -noconnected | 
| C | -connected | RTF_CONNECTED | treat as a connected route | 
|   | -noconnected | ~RTF_CONNECTED | stop treating a connected route | 
| D | RTF_DYNAMIC | created dynamically (redirect) | |
| G | RTF_GATEWAY | forward to dest by intermediary | |
|   | -iface | ~RTF_GATEWAY | destination is directly reachable | 
| H | RTF_HOST | host entry (net otherwise) | |
| L | RTF_LLDATA | local link, generated by ARP or NDP | |
| l | RTF_LOCAL | route represents a local address | |
| M | RTF_MODIFIED | modified dynamically (redirect) | |
| p | -proxy | RTF_ANNOUNCE | make entry a link level proxy | 
| R | -reject | RTF_REJECT | send ICMP unreachable on match | 
|   | -noreject | ~RTF_REJECT | clear reject flag | 
| S | -static | RTF_STATIC | manually added route | 
|   | -nostatic | ~RTF_STATIC | pretend route added automatically | 
| U | RTF_UP | route usable | 
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 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.
route utility exits 0 on success,
  and >0 if an error occurs. This includes the use of the
  get command to look up a route that is incomplete.
route add default
  192.168.0.1route -n showroute add -net 192.168.1.0 -netmask
  255.255.255.240 10.200.0.1flush command is specified, each routing
      table entry deleted is indicated with a message of this form.route command appeared in
  4.2BSD. IPv6 support was added by WIDE/KAME project.
Since NetBSD 8.0,
    -cloned, -nocloned,
    -llinfo and -xresolve were
    obsolete and -cloning and
    -nocloning were deprecated.
    -connected and -noconnected
    appeared in NetBSD 8.0.
Some uses of the -ifa or
    -ifp modifiers with the add command will incorrectly
    fail with a “Network is unreachable” message if there is no
    default route. See case RTM_ADD in
    sys/net/rtsock.c:route_output for details.
| August 29, 2020 | NetBSD 10.1 |