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28 .\" @(#)route.8 8.3 (Berkeley) 3/19/94
29 .\" $FreeBSD: src/sbin/route/route.8,v 1.17.2.9 2003/02/24 00:56:43 trhodes Exp $
36 .Nd manually manipulate the routing tables
49 utility is used to manually manipulate the network
50 routing tables. 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 On SMP systems the route table is replicated. This option allows the
67 route table for a specific cpu to be accessed and exists primarily
68 for debugging purposes.
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
139 modifiers, only routes having destinations with addresses in the
140 delineated family will be deleted.
142 The other commands have the following syntax:
144 .Bd -ragged -offset indent -compact
148 .Op Fl net No \&| Fl host
149 .Ar destination gateway
155 is the destination host or network,
157 is the next-hop intermediary via which packets should be routed.
158 Routes to a particular host may be distinguished from those to
159 a network by interpreting the Internet address specified as the
162 The optional modifiers
166 force the destination to be interpreted as a network or a host, respectively.
170 .Dq local address part
176 is the symbolic name of a network, then the route is
177 assumed to be to a network; otherwise, it is presumed to be a
181 could also be specified in the
182 .Ar net Ns / Ns Ar bits
188 .Fl host Li 128.0.0.32 ;
191 .Fl host Li 128.32.0.130 ;
195 .Fl net Li 128.32.130
201 .Fl net Li 192.168.64 Fl netmask Li 255.255.240.0 .
209 which is the default route.
211 If the destination is directly reachable
212 via an interface requiring
213 no intermediary system to act as a gateway, the
215 modifier should be specified;
216 the gateway given is the address of this host on the common network,
217 indicating the interface to be used for transmission.
218 Alternately, if the interface is point to point the name of the interface
219 itself may be given, in which case the route remains valid even
220 if the local or remote addresses change.
222 The optional modifiers
228 specify that all subsequent addresses are in the
234 or are specified as link-level addresses,
235 and the names must be numeric specifications rather than
241 to achieve the effect of an
244 redirect with the netmask option,
245 or to manually add subnet routes with
246 netmasks different from that of the implied network interface
247 (as would otherwise be communicated using the OSPF or ISIS routing protocols).
248 One specifies an additional ensuing address parameter
249 (to be interpreted as a network mask).
250 The implicit network mask generated in the AF_INET case
251 can be overridden by making sure this option follows the destination parameter.
258 is available instead of the
260 qualifier because non-continuous masks are not allowed in IPv6.
263 specifies network mask of
264 .Li ffff:ffff:0000:0000:0000:0000:0000:0000
266 The default value of prefixlen is 64 to get along with
267 the aggregatable address.
271 Note that the qualifier works only for
275 Routes have associated flags which influence operation of the protocols
276 when sending to destinations matched by the routes.
277 These flags may be set (or sometimes cleared)
278 by indicating the following corresponding modifiers:
280 -cloning RTF_CLONING - generates a new route on use
281 -xresolve RTF_XRESOLVE - emit mesg on use (for external lookup)
282 -iface ~RTF_GATEWAY - destination is directly reachable
283 -static RTF_STATIC - manually added route
284 -nostatic ~RTF_STATIC - pretend route added by kernel or daemon
285 -reject RTF_REJECT - emit an ICMP unreachable when matched
286 -blackhole RTF_BLACKHOLE - silently discard pkts (during updates)
287 -proto1 RTF_PROTO1 - set protocol specific routing flag #1
288 -proto2 RTF_PROTO2 - set protocol specific routing flag #2
289 -llinfo RTF_LLINFO - validly translates proto addr to link addr
292 The optional modifiers
305 provide initial values to quantities maintained in the routing entry
306 by transport level protocols, such as TCP or TP4.
307 These may be individually locked by preceding each such modifier to
311 meta-modifier, or one can
312 specify that all ensuing metrics may be locked by the
320 command where the destination and gateway are not sufficient to specify
323 case where several interfaces may have the
328 modifiers may be used to determine the interface or interface address.
332 modifier specifies that the
334 routing table entry is the
335 .Dq published (proxy-only)
337 entry, as reported by
340 All symbolic names specified for a
344 are looked up first as a host name using
345 .Xr gethostbyname 3 .
346 If this lookup fails,
348 is then used to interpret the name as that of a network.
355 modifiers may be used to specify the desired mpls label
356 operations for the route. Each route may have up to 3
357 label operations assigned to it. The label operations
358 may be combined between them, but specifically the
362 operations may be repeated if the intent is to push or pop
363 more than one label at once. The
365 operation always swaps the outer label and may not be
367 Here are some MPLS route examples:
369 Add an normal inet route, but push an mpls
373 .Bd -ragged -offset indent -compact
376 .Ar destination gateway
381 Add an normal inet route, but double-push an mpls
387 .Bd -ragged -offset indent -compact
390 .Ar destination gateway
397 Add an mpls route for an
401 and swap that label with
404 .Bd -ragged -offset indent -compact
417 utility uses a routing socket and the new message types
418 .Dv RTM_ADD , RTM_DELETE , RTM_GET ,
421 As such, only the super-user may modify
427 .It "add [host \&| network ] %s: gateway %s flags %x"
428 The specified route is being added to the tables. The
429 values printed are from the routing table entry supplied
433 If the gateway address used was not the primary address of the gateway
434 (the first one returned by
435 .Xr gethostbyname 3 ) ,
436 the gateway address is printed numerically as well as symbolically.
437 .It "delete [ host \&| network ] %s: gateway %s flags %x"
438 As above, but when deleting an entry.
442 command is specified, each routing table entry deleted
443 is indicated with a message of this form.
444 .It "Network is unreachable"
445 An attempt to add a route failed because the gateway listed was not
446 on a directly-connected network.
447 The next-hop gateway must be given.
449 A delete operation was attempted for an entry which
450 wasn't present in the tables.
451 .It "routing table overflow"
452 An add operation was attempted, but the system was
453 low on resources and was unable to allocate memory
454 to create the new entry.
455 .It "gateway uses the same route"
458 operation resulted in a route whose gateway uses the
459 same route as the one being changed.
460 The next-hop gateway should be reachable through a different route.
476 The first paragraph may have slightly exaggerated