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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 1.4 2004/03/23 18:25:51 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
84 Print the full width of the data being represented even if it would overflow
90 utility provides six commands:
92 .Bl -tag -width Fl -compact
98 Delete a specific route.
100 Change aspects of a route (such as its gateway).
102 Lookup and display the route for a destination.
104 Print out the route table similar to "netstat \-r" (see
107 Continuously report any changes to the routing information base,
108 routing lookup misses, or suspected network partitionings.
111 The monitor command has the syntax:
113 .Bd -ragged -offset indent -compact
119 The flush command has the syntax:
121 .Bd -ragged -offset indent -compact
130 command is specified,
132 will ``flush'' the routing tables of all gateway entries.
133 When the address family may is specified by any of the
140 modifiers, only routes having destinations with addresses in the
141 delineated family will be deleted.
143 The other commands have the following syntax:
145 .Bd -ragged -offset indent -compact
149 .Op Fl net No \&| Fl host
150 .Ar destination gateway
156 is the destination host or network,
158 is the next-hop intermediary via which packets should be routed.
159 Routes to a particular host may be distinguished from those to
160 a network by interpreting the Internet address specified as the
163 The optional modifiers
167 force the destination to be interpreted as a network or a host, respectively.
171 .Dq local address part
177 is the symbolic name of a network, then the route is
178 assumed to be to a network; otherwise, it is presumed to be a
182 could also be specified in the
183 .Ar net Ns / Ns Ar bits
189 .Fl host Li 128.0.0.32 ;
192 .Fl host Li 128.32.0.130 ;
196 .Fl net Li 128.32.130
202 .Fl net Li 192.168.64 Fl netmask Li 255.255.240.0 .
210 which is the default route.
212 If the destination is directly reachable
213 via an interface requiring
214 no intermediary system to act as a gateway, the
216 modifier should be specified;
217 the gateway given is the address of this host on the common network,
218 indicating the interface to be used for transmission.
219 Alternately, if the interface is point to point the name of the interface
220 itself may be given, in which case the route remains valid even
221 if the local or remote addresses change.
223 The optional modifiers
229 specify that all subsequent addresses are in the
235 or are specified as link-level addresses,
236 and the names must be numeric specifications rather than
242 to achieve the effect of an
245 redirect with the netmask option,
246 or to manually add subnet routes with
247 netmasks different from that of the implied network interface
248 (as would otherwise be communicated using the OSPF or ISIS routing protocols).
249 One specifies an additional ensuing address parameter
250 (to be interpreted as a network mask).
251 The implicit network mask generated in the AF_INET case
252 can be overridden by making sure this option follows the destination parameter.
259 is available instead of the
261 qualifier because non-continuous masks are not allowed in IPv6.
264 specifies network mask of
265 .Li ffff:ffff:0000:0000:0000:0000:0000:0000
267 The default value of prefixlen is 64 to get along with
268 the aggregatable address.
272 Note that the qualifier works only for
276 Routes have associated flags which influence operation of the protocols
277 when sending to destinations matched by the routes.
278 These flags may be set (or sometimes cleared)
279 by indicating the following corresponding modifiers:
281 -cloning RTF_CLONING - generates a new route on use
282 -xresolve RTF_XRESOLVE - emit mesg on use (for external lookup)
283 -iface ~RTF_GATEWAY - destination is directly reachable
284 -static RTF_STATIC - manually added route
285 -nostatic ~RTF_STATIC - pretend route added by kernel or daemon
286 -reject RTF_REJECT - emit an ICMP unreachable when matched
287 -blackhole RTF_BLACKHOLE - silently discard pkts (during updates)
288 -proto1 RTF_PROTO1 - set protocol specific routing flag #1
289 -proto2 RTF_PROTO2 - set protocol specific routing flag #2
290 -llinfo RTF_LLINFO - validly translates proto addr to link addr
293 The optional modifiers
303 provide initial values to quantities maintained in the routing entry
304 by transport level protocols, such as TCP or TP4.
305 These may be individually locked by preceding each such modifier to
309 meta-modifier, or one can
310 specify that all ensuing metrics may be locked by the
318 command where the destination and gateway are not sufficient to specify
321 case where several interfaces may have the
326 modifiers may be used to determine the interface or interface address.
330 modifier specifies that the
332 routing table entry is the
333 .Dq published (proxy-only)
335 entry, as reported by
338 All symbolic names specified for a
342 are looked up first as a host name using
343 .Xr gethostbyname 3 .
344 If this lookup fails,
346 is then used to interpret the name as that of a network.
350 utility uses a routing socket and the new message types
351 .Dv RTM_ADD , RTM_DELETE , RTM_GET ,
354 As such, only the super-user may modify
358 .It "add [host \&| network ] %s: gateway %s flags %x"
359 The specified route is being added to the tables. The
360 values printed are from the routing table entry supplied
364 If the gateway address used was not the primary address of the gateway
365 (the first one returned by
366 .Xr gethostbyname 3 ) ,
367 the gateway address is printed numerically as well as symbolically.
368 .It "delete [ host \&| network ] %s: gateway %s flags %x"
369 As above, but when deleting an entry.
373 command is specified, each routing table entry deleted
374 is indicated with a message of this form.
375 .It "Network is unreachable"
376 An attempt to add a route failed because the gateway listed was not
377 on a directly-connected network.
378 The next-hop gateway must be given.
380 A delete operation was attempted for an entry which
381 wasn't present in the tables.
382 .It "routing table overflow"
383 An add operation was attempted, but the system was
384 low on resources and was unable to allocate memory
385 to create the new entry.
386 .It "gateway uses the same route"
389 operation resulted in a route whose gateway uses the
390 same route as the one being changed.
391 The next-hop gateway should be reachable through a different route.
409 The first paragraph may have slightly exaggerated