ROUTE(8)						    BSD 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 symbolic
	     names and numerical equivalents can be quite time consuming, and may require correct operation of the network; thus it may be expedi-
	     ent to forgo this, especially when attempting to repair networking operations).

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

     -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 contiguous
	     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 partitionings.

     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, -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 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 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 for-
     mat.

     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 transmis-
     sion.

     The optional modifiers -xns, -osi, -atalk, and -link specify that all subsequent addresses are in the XNS, OSI, or AppleTalk address fami-
     lies, 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 modifiers -mpls and -tag specify that all subsequent addresses are in the MPLS address family.  See mpls(4) for examples about
     setting routes involving MPLS.

     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
     protocols).  One specifies an additional ensuing address parameter (to be interpreted as a network mask).	The implicit network mask gener-
     ated 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 modifiers:

     -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
     -noreject	  ~RTF_REJECT	  - clear reject flag
     -blackhole    RTF_BLACKHOLE  - silently discard pkts (during updates)
     -noblackhole ~RTF_BLACKHOLE  - clear blackhole flag
     -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
     -proxy	   RTF_ANNOUNCE   - make entry a link level proxy

     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 (as in the ISO case where several inter-
     faces 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), mpls(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 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.

BSD
								  August 6, 2006							       BSD