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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 $
40 .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 On SMP systems the route table is replicated. This option allows the
71 route table for a specific cpu to be accessed and exists primarily
72 for debugging purposes.
74 Bypass attempts to print host and network names symbolically
75 when reporting actions. (The process of translating between symbolic
76 names and numerical equivalents can be quite time consuming, and
77 may require correct operation of the network; thus it may be expedient
78 to forget this, especially when attempting to repair networking operations).
80 (verbose) Print additional details.
82 Suppress all output from the
88 Print the full width of the data being represented even if it would overflow
94 utility provides six commands:
96 .Bl -tag -width Fl -compact
102 Delete a specific route.
104 Change aspects of a route (such as its gateway).
106 Lookup and display the route for a destination.
108 Print out the route table similar to "netstat \-r" (see
111 Continuously report any changes to the routing information base,
112 routing lookup misses, or suspected network partitionings.
115 The monitor command has the syntax:
117 .Bd -ragged -offset indent -compact
123 The flush command has the syntax:
125 .Bd -ragged -offset indent -compact
134 command is specified,
136 will ``flush'' the routing tables of all gateway entries.
137 When the address family may is specified by any of the
143 modifiers, only routes having destinations with addresses in the
144 delineated family will be deleted.
146 The other commands have the following syntax:
148 .Bd -ragged -offset indent -compact
152 .Op Fl net No \&| Fl host
153 .Ar destination gateway
159 is the destination host or network,
161 is the next-hop intermediary via which packets should be routed.
162 Routes to a particular host may be distinguished from those to
163 a network by interpreting the Internet address specified as the
166 The optional modifiers
170 force the destination to be interpreted as a network or a host, respectively.
174 .Dq local address part
180 is the symbolic name of a network, then the route is
181 assumed to be to a network; otherwise, it is presumed to be a
185 could also be specified in the
186 .Ar net Ns / Ns Ar bits
192 .Fl host Li 128.0.0.32 ;
195 .Fl host Li 128.32.0.130 ;
199 .Fl net Li 128.32.130
205 .Fl net Li 192.168.64 Fl netmask Li 255.255.240.0 .
213 which is the default route.
215 If the destination is directly reachable
216 via an interface requiring
217 no intermediary system to act as a gateway, the
219 modifier should be specified;
220 the gateway given is the address of this host on the common network,
221 indicating the interface to be used for transmission.
222 Alternately, if the interface is point to point the name of the interface
223 itself may be given, in which case the route remains valid even
224 if the local or remote addresses change.
226 The optional modifiers
232 specify that all subsequent addresses are in the
238 or are specified as link-level addresses,
239 and the names must be numeric specifications rather than
245 to achieve the effect of an
248 redirect with the netmask option,
249 or to manually add subnet routes with
250 netmasks different from that of the implied network interface
251 (as would otherwise be communicated using the OSPF or ISIS routing protocols).
252 One specifies an additional ensuing address parameter
253 (to be interpreted as a network mask).
254 The implicit network mask generated in the AF_INET case
255 can be overridden by making sure this option follows the destination parameter.
262 is available instead of the
264 qualifier because non-continuous masks are not allowed in IPv6.
267 specifies network mask of
268 .Li ffff:ffff:0000:0000:0000:0000:0000:0000
270 The default value of prefixlen is 64 to get along with
271 the aggregatable address.
275 Note that the qualifier works only for
279 Routes have associated flags which influence operation of the protocols
280 when sending to destinations matched by the routes.
281 These flags may be set (or sometimes cleared)
282 by indicating the following corresponding modifiers:
284 -cloning RTF_CLONING - generates a new route on use
285 -xresolve RTF_XRESOLVE - emit mesg on use (for external lookup)
286 -iface ~RTF_GATEWAY - destination is directly reachable
287 -static RTF_STATIC - manually added route
288 -nostatic ~RTF_STATIC - pretend route added by kernel or daemon
289 -reject RTF_REJECT - emit an ICMP unreachable when matched
290 -blackhole RTF_BLACKHOLE - silently discard pkts (during updates)
291 -proto1 RTF_PROTO1 - set protocol specific routing flag #1
292 -proto2 RTF_PROTO2 - set protocol specific routing flag #2
293 -llinfo RTF_LLINFO - validly translates proto addr to link addr
296 The optional modifiers
306 provide initial values to quantities maintained in the routing entry
307 by transport level protocols, such as TCP or TP4.
308 These may be individually locked by preceding each such modifier to
312 meta-modifier, or one can
313 specify that all ensuing metrics may be locked by the
321 command where the destination and gateway are not sufficient to specify
324 case where several interfaces may have the
329 modifiers may be used to determine the interface or interface address.
333 modifier specifies that the
335 routing table entry is the
336 .Dq published (proxy-only)
338 entry, as reported by
341 All symbolic names specified for a
345 are looked up first as a host name using
346 .Xr gethostbyname 3 .
347 If this lookup fails,
349 is then used to interpret the name as that of a network.
356 modifiers may be used to specify the desired mpls label
357 operations for the route. Each route may have up to 3
358 label operations assigned to it. The label operations
359 may be combined between them, but specifically the
363 operations may be repeated if the intent is to push or pop
364 more than one label at once. The
366 operation always swaps the outer label and may not be
368 Here are some MPLS route examples:
370 Add an normal inet route, but push an mpls
374 .Bd -ragged -offset indent -compact
377 .Ar destination gateway
382 Add an normal inet route, but double-push an mpls
388 .Bd -ragged -offset indent -compact
391 .Ar destination gateway
398 Add an mpls route for an
402 and swap that label with
405 .Bd -ragged -offset indent -compact
418 utility uses a routing socket and the new message types
419 .Dv RTM_ADD , RTM_DELETE , RTM_GET ,
422 As such, only the super-user may modify
428 .It "add [host \&| network ] %s: gateway %s flags %x"
429 The specified route is being added to the tables. The
430 values printed are from the routing table entry supplied
434 If the gateway address used was not the primary address of the gateway
435 (the first one returned by
436 .Xr gethostbyname 3 ) ,
437 the gateway address is printed numerically as well as symbolically.
438 .It "delete [ host \&| network ] %s: gateway %s flags %x"
439 As above, but when deleting an entry.
443 command is specified, each routing table entry deleted
444 is indicated with a message of this form.
445 .It "Network is unreachable"
446 An attempt to add a route failed because the gateway listed was not
447 on a directly-connected network.
448 The next-hop gateway must be given.
450 A delete operation was attempted for an entry which
451 wasn't present in the tables.
452 .It "routing table overflow"
453 An add operation was attempted, but the system was
454 low on resources and was unable to allocate memory
455 to create the new entry.
456 .It "gateway uses the same route"
459 operation resulted in a route whose gateway uses the
460 same route as the one being changed.
461 The next-hop gateway should be reachable through a different route.
477 The first paragraph may have slightly exaggerated