route man page on 4.4BSD

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

     route — manually manipulate the routing tables.

     route [-nqv] 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(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

     -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),

     -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‐

     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, or -inet modifiers, only routes having destina‐
     tions with addresses in the delineated family will be deleted.

     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 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
     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; 128.32.130 is
     interpreted as -host; -net 128.32 is interpreted as; and -net 128.32.130 is interpreted as

     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, and -link specify that all subsequent
     addresses are in the XNS OSI 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.

     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‐

     -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 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.

     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

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

     The route command appeared in 4.2BSD.

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

4.4BSD				 June 1, 1994				4.4BSD

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