DESCRIPTION

     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(8), 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 discussed in
     route(4).

     The following options are available:

     -n      Bypass 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 forget this, especially when attempting to repair
             networking operations).

     -v      (verbose) Print additional details.

     -q      Suppress all output.

     The route utility provides six commands:

     add         Add a route.
     flush       Remove all routes.
     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 partition-
                 ings.

     The monitor command has the syntax:

           route [-n] monitor

     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 may is specified
     by any of the -osi, -xns, -atalk, -inet6, or -inet modifiers, only routes
     having destinations with addresses in the delineated family will be
     deleted.

     The other commands have the following syntax:

           route [-n] command [-net | -host] destination gateway [netmask]

     128.32.0.0; -net 128.32.130 is interpreted as 128.32.130.0; and
     192.168.64/20 is interpreted as -net 192.168.64 -netmask 255.255.240.0.

     A destination of default is a synonym for -net 0.0.0.0, which is the
     default route.

     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.  Alter-
     nately, if the interface is point to point the name of the interface
     itself may be given, in which case the route remains valid even if the
     local or remote addresses change.

     The optional modifiers -xns, -osi, and -link specify that all subsequent
     addresses are in the XNS, OSI, or AppleTalk address families, or are
     specified as link-level addresses, and the names must be numeric specifi-
     cations rather than symbolic names.

     The optional -netmask modifier 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 proto-
     cols).  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.

     For AF_INET6, the -prefixlen qualifier is available instead of the -mask
     qualifier because non-continuous masks are not allowed in IPv6.  For
     example, -prefixlen 32 specifies network mask of
     ffff:ffff:0000:0000:0000:0000:0000:0000 to be used.  The default value of
     prefixlen is 64 to get along with the aggregatable address.  But 0 is
     assumed if default is specified.  Note that the qualifier works only for
     AF_INET6 address family.

     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 mod-
     ifiers:

     -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


     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.

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(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 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.

     gateway uses the same route  A change operation resulted in a route whose
     gateway uses the same route as the one being changed.  The next-hop gate-
     way should be reachable through a different route.

     The route utility exits 0 on success, and >0 if an error occurs.

SEE ALSO

     netintro(4), route(4), arp(8), routed(8)

HISTORY

     The route command appeared in 4.2BSD.

BUGS

     The first paragraph may have slightly exaggerated routed(8)'s abilities.

4.4BSD                           June 8, 2001                           4.4BSD