1 .\" Copyright (c) 1983, 1991, 1993
2 .\" The Regents of the University of California. All rights reserved.
4 .\" Redistribution and use in source and binary forms, with or without
5 .\" modification, are permitted provided that the following conditions
7 .\" 1. Redistributions of source code must retain the above copyright
8 .\" notice, this list of conditions and the following disclaimer.
9 .\" 2. Redistributions in binary form must reproduce the above copyright
10 .\" notice, this list of conditions and the following disclaimer in the
11 .\" documentation and/or other materials provided with the distribution.
12 .\" 4. Neither the name of the University nor the names of its contributors
13 .\" may be used to endorse or promote products derived from this software
14 .\" without specific prior written permission.
16 .\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
17 .\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
18 .\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
19 .\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
20 .\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
21 .\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
22 .\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
23 .\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
24 .\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
25 .\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
28 .\" @(#)route.8 8.3 (Berkeley) 3/19/94
36 .Nd manually manipulate the routing tables
48 utility is used to manually manipulate the network
50 It normally is not needed, as a
51 system routing table management daemon, such as
53 should tend to this task.
57 utility supports a limited number of general options,
58 but a rich command language, enabling the user to specify
59 any arbitrary request that could be delivered via the
60 programmatic interface discussed in
63 The following options are available:
64 .Bl -tag -width indent
66 Run in debug-only mode, i.e., do not actually modify the routing table.
68 Bypass attempts to print host and network names symbolically
69 when reporting actions.
70 (The process of translating between symbolic
71 names and numerical equivalents can be quite time consuming, and
72 may require correct operation of the network; thus it may be expedient
73 to forget this, especially when attempting to repair networking operations).
75 (verbose) Print additional details.
77 Suppress all output from the
78 .Cm add , change , delete ,
86 utility provides the following commands:
88 .Bl -tag -width Fl -compact
94 Delete a specific route.
100 Change aspects of a route (such as its gateway).
102 Lookup and display the route for a destination.
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
337 modifier specifies that a cloning mask is present.
338 This specifies the mask applied when determining if a child route
340 It is only applicable to network routes with the
344 All symbolic names specified for a
348 are looked up first as a host name using
349 .Xr gethostbyname 3 .
350 If this lookup fails,
352 is then used to interpret the name as that of a network.
356 utility uses a routing socket and the new message types
357 .Dv RTM_ADD , RTM_DELETE , RTM_GET ,
360 As such, only the super-user may modify
366 .It "add [host \&| network ] %s: gateway %s flags %x"
367 The specified route is being added to the tables.
369 values printed are from the routing table entry supplied
373 If the gateway address used was not the primary address of the gateway
374 (the first one returned by
375 .Xr gethostbyname 3 ) ,
376 the gateway address is printed numerically as well as symbolically.
377 .It "delete [ host \&| network ] %s: gateway %s flags %x"
378 As above, but when deleting an entry.
382 command is specified, each routing table entry deleted
383 is indicated with a message of this form.
384 .It "Network is unreachable"
385 An attempt to add a route failed because the gateway listed was not
386 on a directly-connected network.
387 The next-hop gateway must be given.
389 A delete operation was attempted for an entry which
390 was not present in the tables.
391 .It "routing table overflow"
392 An add operation was attempted, but the system was
393 low on resources and was unable to allocate memory
394 to create the new entry.
395 .It "gateway uses the same route"
398 operation resulted in a route whose gateway uses the
399 same route as the one being changed.
400 The next-hop gateway should be reachable through a different route.
416 The first paragraph may have slightly exaggerated
420 Currently, routes with the
422 flag set need to have the gateway set to an instance of the
426 option, for the flag to have any effect; unless IP fast forwarding
427 is enabled, in which case the meaning of the flag will always