route(8) - NetBSD Manual Pages

ROUTE(8)                NetBSD System Manager's Manual                ROUTE(8)


NAME

     route -- manually manipulate the routing tables


SYNOPSIS

     route [-fnqSsv] command [[modifiers] args]


DESCRIPTION

     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).

     -f      Remove all routes (as per flush).  If used in conjunction with
             the add, change, delete or get commands, route removes the routes
             before performing the command.

     -n      Bypasses attempts to print host and network names symbolically
             when reporting actions.  (The process of translating between sym-
             bolic names and numerical equivalents can be quite time consum-
             ing, and may require correct operation of the network; thus it
             may be expedient to forgo this, especially when attempting to
             repair networking operations).

     -q      Suppress all output from commands that manipulate the routing ta-
             ble.

     -S      Print a space when a flag is missing so that flags are vertically
             aligned instead of printing the flags that are set as a contigu-
             ous string.

     -s      (short) Suppresses all output from a get command except for the
             actual gateway that will be used.  How the gateway is printed
             depends on the type of route being looked up.

     -v      (verbose) Print additional details.

     The route utility provides several commands:

     add         Add a route.
     flush       Remove all routes.
     flushall    Remove all routes including the default gateway.
     delete      Delete a specific route.
     change      Change aspects of a route (such as its gateway).
     get         Lookup and display the route for a destination.
     show        Print out the route table similar to "netstat -r" (see
                 netstat(1)).
     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 is specified by
     any of the -osi, -xns, -atalk, -inet, or -inet6 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 gateway

     where 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 inter-
     preting 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 sym-
     bolic 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 -xns, -osi, -atalk, 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
     specifications rather than symbolic names.

     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 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.  -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 may be
     set (or sometimes cleared) by indicating the following corresponding mod-
     ifiers:

     -cloning    RTF_CLONING    - generates a new route on use
     -nocloning ~RTF_CLONING    - stop generating new routes on use
     -cloned     RTF_CLONED     - cloned route generated by RTF_CLONING
     -nocloned  ~RTF_CLONED     - prevent removal with RTF_CLONING parent
     -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 suf-
     ficient to specify the route (as in the ISO 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.


EXIT STATUS

     The 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 incom-
     plete.


EXAMPLES

     This sets the default route to 192.168.0.1:
           route add default 192.168.0.1
     This shows all routes, without DNS resolution (this is useful if the DNS
     is not available):
           route -n show
     To install a static route through 10.200.0.1 to reach the network
     192.168.1.0/28, use this:
           route add -net 192.168.1.0 -netmask 255.255.255.240 10.200.0.1


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.

     Permission denied
             The attempted operation is privileged.  Only root may modify the
             routing tables.  These privileges are enforced by the kernel.


SEE ALSO

     esis(4), netintro(4), route(4), routed(8), sysctl(8)


HISTORY

     The route command appeared in 4.2BSD.  IPv6 support was added by
     WIDE/KAME project.


BUGS

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

     Some uses of the -ifa or -ifp modifiers with the add command will incor-
     rectly 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.

NetBSD 5.1                      August 6, 2006                      NetBSD 5.1