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32 .\" @(#)route.8 8.3 (Berkeley) 3/19/94
33 .\" $FreeBSD: src/sbin/route/route.8,v 1.17.2.9 2003/02/24 00:56:43 trhodes Exp $
34 .\" $DragonFly: src/sbin/route/route.8,v 1.3 2004/03/23 17:56:29 dillon Exp $
41 .Nd manually manipulate the routing tables
53 utility is used to manually manipulate the network
54 routing tables. It normally is not needed, as a
55 system routing table management daemon such as
57 should tend to this task.
61 utility supports a limited number of general options,
62 but a rich command language, enabling the user to specify
63 any arbitrary request that could be delivered via the
64 programmatic interface discussed in
67 The following options are available:
68 .Bl -tag -width indent
70 Bypass attempts to print host and network names symbolically
71 when reporting actions. (The process of translating between symbolic
72 names and numerical equivalents can be quite time consuming, and
73 may require correct operation of the network; thus it may be expedient
74 to forget this, especially when attempting to repair networking operations).
76 (verbose) Print additional details.
78 Suppress all output from the
87 utility provides six commands:
89 .Bl -tag -width Fl -compact
95 Delete a specific route.
97 Change aspects of a route (such as its gateway).
99 Lookup and display the route for a destination.
101 Print out the route table similar to "netstat \-r" (see
104 Continuously report any changes to the routing information base,
105 routing lookup misses, or suspected network partitionings.
108 The monitor command has the syntax:
110 .Bd -ragged -offset indent -compact
116 The flush command has the syntax:
118 .Bd -ragged -offset indent -compact
127 command is specified,
129 will ``flush'' the routing tables of all gateway entries.
130 When the address family may is specified by any of the
137 modifiers, only routes having destinations with addresses in the
138 delineated family will be deleted.
140 The other commands have the following syntax:
142 .Bd -ragged -offset indent -compact
146 .Op Fl net No \&| Fl host
147 .Ar destination gateway
153 is the destination host or network,
155 is the next-hop intermediary via which packets should be routed.
156 Routes to a particular host may be distinguished from those to
157 a network by interpreting the Internet address specified as the
160 The optional modifiers
164 force the destination to be interpreted as a network or a host, respectively.
168 .Dq local address part
174 is the symbolic name of a network, then the route is
175 assumed to be to a network; otherwise, it is presumed to be a
179 could also be specified in the
180 .Ar net Ns / Ns Ar bits
186 .Fl host Li 128.0.0.32 ;
189 .Fl host Li 128.32.0.130 ;
193 .Fl net Li 128.32.130
199 .Fl net Li 192.168.64 Fl netmask Li 255.255.240.0 .
207 which is the default route.
209 If the destination is directly reachable
210 via an interface requiring
211 no intermediary system to act as a gateway, the
213 modifier should be specified;
214 the gateway given is the address of this host on the common network,
215 indicating the interface to be used for transmission.
216 Alternately, if the interface is point to point the name of the interface
217 itself may be given, in which case the route remains valid even
218 if the local or remote addresses change.
220 The optional modifiers
226 specify that all subsequent addresses are in the
232 or are specified as link-level addresses,
233 and the names must be numeric specifications rather than
239 to achieve the effect of an
242 redirect with the netmask option,
243 or to manually add subnet routes with
244 netmasks different from that of the implied network interface
245 (as would otherwise be communicated using the OSPF or ISIS routing protocols).
246 One specifies an additional ensuing address parameter
247 (to be interpreted as a network mask).
248 The implicit network mask generated in the AF_INET case
249 can be overridden by making sure this option follows the destination parameter.
256 is available instead of the
258 qualifier because non-continuous masks are not allowed in IPv6.
261 specifies network mask of
262 .Li ffff:ffff:0000:0000:0000:0000:0000:0000
264 The default value of prefixlen is 64 to get along with
265 the aggregatable address.
269 Note that the qualifier works only for
273 Routes have associated flags which influence operation of the protocols
274 when sending to destinations matched by the routes.
275 These flags may be set (or sometimes cleared)
276 by indicating the following corresponding modifiers:
278 -cloning RTF_CLONING - generates a new route on use
279 -xresolve RTF_XRESOLVE - emit mesg on use (for external lookup)
280 -iface ~RTF_GATEWAY - destination is directly reachable
281 -static RTF_STATIC - manually added route
282 -nostatic ~RTF_STATIC - pretend route added by kernel or daemon
283 -reject RTF_REJECT - emit an ICMP unreachable when matched
284 -blackhole RTF_BLACKHOLE - silently discard pkts (during updates)
285 -proto1 RTF_PROTO1 - set protocol specific routing flag #1
286 -proto2 RTF_PROTO2 - set protocol specific routing flag #2
287 -llinfo RTF_LLINFO - validly translates proto addr to link addr
290 The optional modifiers
300 provide initial values to quantities maintained in the routing entry
301 by transport level protocols, such as TCP or TP4.
302 These may be individually locked by preceding each such modifier to
306 meta-modifier, or one can
307 specify that all ensuing metrics may be locked by the
315 command where the destination and gateway are not sufficient to specify
318 case where several interfaces may have the
323 modifiers may be used to determine the interface or interface address.
327 modifier specifies that the
329 routing table entry is the
330 .Dq published (proxy-only)
332 entry, as reported by
335 All symbolic names specified for a
339 are looked up first as a host name using
340 .Xr gethostbyname 3 .
341 If this lookup fails,
343 is then used to interpret the name as that of a network.
347 utility uses a routing socket and the new message types
348 .Dv RTM_ADD , RTM_DELETE , RTM_GET ,
351 As such, only the super-user may modify
355 .It "add [host \&| network ] %s: gateway %s flags %x"
356 The specified route is being added to the tables. The
357 values printed are from the routing table entry supplied
361 If the gateway address used was not the primary address of the gateway
362 (the first one returned by
363 .Xr gethostbyname 3 ) ,
364 the gateway address is printed numerically as well as symbolically.
365 .It "delete [ host \&| network ] %s: gateway %s flags %x"
366 As above, but when deleting an entry.
370 command is specified, each routing table entry deleted
371 is indicated with a message of this form.
372 .It "Network is unreachable"
373 An attempt to add a route failed because the gateway listed was not
374 on a directly-connected network.
375 The next-hop gateway must be given.
377 A delete operation was attempted for an entry which
378 wasn't present in the tables.
379 .It "routing table overflow"
380 An add operation was attempted, but the system was
381 low on resources and was unable to allocate memory
382 to create the new entry.
383 .It "gateway uses the same route"
386 operation resulted in a route whose gateway uses the
387 same route as the one being changed.
388 The next-hop gateway should be reachable through a different route.
406 The first paragraph may have slightly exaggerated