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

     route -- manually manipulate the routing tables

     route [-dnqtv] command [[modifiers] args]

     Route is a	utility	used to	manually manipulate the	network	routing	ta-
     bles.  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

     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 ex-
	     pedient to	forgot this, especially	when attempting	to repair net-
	     working 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 ta-
     bles of all gateway entries.  When	the address family may is specified by
     any of the	-osi, -xns, -atalk, 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

     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 net-
     work; otherwise, it is presumed to	be a route to a	host.

     For example, 128.32 is interpreted	as -host; 128.32.130	is in-
     terpreted as -host; -net 128.32 is interpreted as; and -net 128.32.130 is	interpreted as

     A destination of default is a synonym for -net, which is the de-
     fault 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 it-
     self may be given,	in which case the route	remains	valid even if the lo-
     cal or remote addresses change.

     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 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 in-
     terpreted 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 en-
     suing 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 de-
     termine 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 re-
	     sources and was unable to allocate	memory to create the new en-

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

     The route command appeared	in 4.2BSD.

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

4.4BSD				March 19, 1994				4.4BSD


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