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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 1.2 2003/06/17 04:27:34 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 Continuously report any changes to the routing information base,
102 routing lookup misses, or suspected network partitionings.
105 The monitor command has the syntax:
107 .Bd -ragged -offset indent -compact
113 The flush command has the syntax:
115 .Bd -ragged -offset indent -compact
124 command is specified,
126 will ``flush'' the routing tables of all gateway entries.
127 When the address family may is specified by any of the
134 modifiers, only routes having destinations with addresses in the
135 delineated family will be deleted.
137 The other commands have the following syntax:
139 .Bd -ragged -offset indent -compact
143 .Op Fl net No \&| Fl host
144 .Ar destination gateway
150 is the destination host or network,
152 is the next-hop intermediary via which packets should be routed.
153 Routes to a particular host may be distinguished from those to
154 a network by interpreting the Internet address specified as the
157 The optional modifiers
161 force the destination to be interpreted as a network or a host, respectively.
165 .Dq local address part
171 is the symbolic name of a network, then the route is
172 assumed to be to a network; otherwise, it is presumed to be a
176 could also be specified in the
177 .Ar net Ns / Ns Ar bits
183 .Fl host Li 128.0.0.32 ;
186 .Fl host Li 128.32.0.130 ;
190 .Fl net Li 128.32.130
196 .Fl net Li 192.168.64 Fl netmask Li 255.255.240.0 .
204 which is the default route.
206 If the destination is directly reachable
207 via an interface requiring
208 no intermediary system to act as a gateway, the
210 modifier should be specified;
211 the gateway given is the address of this host on the common network,
212 indicating the interface to be used for transmission.
213 Alternately, if the interface is point to point the name of the interface
214 itself may be given, in which case the route remains valid even
215 if the local or remote addresses change.
217 The optional modifiers
223 specify that all subsequent addresses are in the
229 or are specified as link-level addresses,
230 and the names must be numeric specifications rather than
236 to achieve the effect of an
239 redirect with the netmask option,
240 or to manually add subnet routes with
241 netmasks different from that of the implied network interface
242 (as would otherwise be communicated using the OSPF or ISIS routing protocols).
243 One specifies an additional ensuing address parameter
244 (to be interpreted as a network mask).
245 The implicit network mask generated in the AF_INET case
246 can be overridden by making sure this option follows the destination parameter.
253 is available instead of the
255 qualifier because non-continuous masks are not allowed in IPv6.
258 specifies network mask of
259 .Li ffff:ffff:0000:0000:0000:0000:0000:0000
261 The default value of prefixlen is 64 to get along with
262 the aggregatable address.
266 Note that the qualifier works only for
270 Routes have associated flags which influence operation of the protocols
271 when sending to destinations matched by the routes.
272 These flags may be set (or sometimes cleared)
273 by indicating the following corresponding modifiers:
275 -cloning RTF_CLONING - generates a new route on use
276 -xresolve RTF_XRESOLVE - emit mesg on use (for external lookup)
277 -iface ~RTF_GATEWAY - destination is directly reachable
278 -static RTF_STATIC - manually added route
279 -nostatic ~RTF_STATIC - pretend route added by kernel or daemon
280 -reject RTF_REJECT - emit an ICMP unreachable when matched
281 -blackhole RTF_BLACKHOLE - silently discard pkts (during updates)
282 -proto1 RTF_PROTO1 - set protocol specific routing flag #1
283 -proto2 RTF_PROTO2 - set protocol specific routing flag #2
284 -llinfo RTF_LLINFO - validly translates proto addr to link addr
287 The optional modifiers
297 provide initial values to quantities maintained in the routing entry
298 by transport level protocols, such as TCP or TP4.
299 These may be individually locked by preceding each such modifier to
303 meta-modifier, or one can
304 specify that all ensuing metrics may be locked by the
312 command where the destination and gateway are not sufficient to specify
315 case where several interfaces may have the
320 modifiers may be used to determine the interface or interface address.
324 modifier specifies that the
326 routing table entry is the
327 .Dq published (proxy-only)
329 entry, as reported by
332 All symbolic names specified for a
336 are looked up first as a host name using
337 .Xr gethostbyname 3 .
338 If this lookup fails,
340 is then used to interpret the name as that of a network.
344 utility uses a routing socket and the new message types
345 .Dv RTM_ADD , RTM_DELETE , RTM_GET ,
348 As such, only the super-user may modify
352 .It "add [host \&| network ] %s: gateway %s flags %x"
353 The specified route is being added to the tables. The
354 values printed are from the routing table entry supplied
358 If the gateway address used was not the primary address of the gateway
359 (the first one returned by
360 .Xr gethostbyname 3 ) ,
361 the gateway address is printed numerically as well as symbolically.
362 .It "delete [ host \&| network ] %s: gateway %s flags %x"
363 As above, but when deleting an entry.
367 command is specified, each routing table entry deleted
368 is indicated with a message of this form.
369 .It "Network is unreachable"
370 An attempt to add a route failed because the gateway listed was not
371 on a directly-connected network.
372 The next-hop gateway must be given.
374 A delete operation was attempted for an entry which
375 wasn't present in the tables.
376 .It "routing table overflow"
377 An add operation was attempted, but the system was
378 low on resources and was unable to allocate memory
379 to create the new entry.
380 .It "gateway uses the same route"
383 operation resulted in a route whose gateway uses the
384 same route as the one being changed.
385 The next-hop gateway should be reachable through a different route.
403 The first paragraph may have slightly exaggerated