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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
138 modifiers, only routes having destinations with addresses in the
139 delineated family will be deleted.
141 The other commands have the following syntax:
143 .Bd -ragged -offset indent -compact
147 .Op Fl net No \&| Fl host
148 .Ar destination gateway
154 is the destination host or network,
156 is the next-hop intermediary via which packets should be routed.
157 Routes to a particular host may be distinguished from those to
158 a network by interpreting the Internet address specified as the
161 The optional modifiers
165 force the destination to be interpreted as a network or a host, respectively.
169 .Dq local address part
175 is the symbolic name of a network, then the route is
176 assumed to be to a network; otherwise, it is presumed to be a
180 could also be specified in the
181 .Ar net Ns / Ns Ar bits
187 .Fl host Li 128.0.0.32 ;
190 .Fl host Li 128.32.0.130 ;
194 .Fl net Li 128.32.130
200 .Fl net Li 192.168.64 Fl netmask Li 255.255.240.0 .
208 which is the default route.
210 If the destination is directly reachable
211 via an interface requiring
212 no intermediary system to act as a gateway, the
214 modifier should be specified;
215 the gateway given is the address of this host on the common network,
216 indicating the interface to be used for transmission.
217 Alternately, if the interface is point to point the name of the interface
218 itself may be given, in which case the route remains valid even
219 if the local or remote addresses change.
221 The optional modifiers
226 specify that all subsequent addresses are in the
231 or are specified as link-level addresses,
232 and the names must be numeric specifications rather than
238 to achieve the effect of an
241 redirect with the netmask option,
242 or to manually add subnet routes with
243 netmasks different from that of the implied network interface
244 (as would otherwise be communicated using the OSPF or ISIS routing protocols).
245 One specifies an additional ensuing address parameter
246 (to be interpreted as a network mask).
247 The implicit network mask generated in the AF_INET case
248 can be overridden by making sure this option follows the destination parameter.
255 is available instead of the
257 qualifier because non-continuous masks are not allowed in IPv6.
260 specifies network mask of
261 .Li ffff:ffff:0000:0000:0000:0000:0000:0000
263 The default value of prefixlen is 64 to get along with
264 the aggregatable address.
268 Note that the qualifier works only for
272 Routes have associated flags which influence operation of the protocols
273 when sending to destinations matched by the routes.
274 These flags may be set (or sometimes cleared)
275 by indicating the following corresponding modifiers:
277 -cloning RTF_CLONING - generates a new route on use
278 -xresolve RTF_XRESOLVE - emit mesg on use (for external lookup)
279 -iface ~RTF_GATEWAY - destination is directly reachable
280 -static RTF_STATIC - manually added route
281 -nostatic ~RTF_STATIC - pretend route added by kernel or daemon
282 -reject RTF_REJECT - emit an ICMP unreachable when matched
283 -blackhole RTF_BLACKHOLE - silently discard pkts (during updates)
284 -proto1 RTF_PROTO1 - set protocol specific routing flag #1
285 -proto2 RTF_PROTO2 - set protocol specific routing flag #2
286 -llinfo RTF_LLINFO - validly translates proto addr to link addr
289 The optional modifiers
302 provide initial values to quantities maintained in the routing entry
303 by transport level protocols, such as TCP or TP4.
304 These may be individually locked by preceding each such modifier to
308 meta-modifier, or one can
309 specify that all ensuing metrics may be locked by the
317 command where the destination and gateway are not sufficient to specify
320 case where several interfaces may have the
325 modifiers may be used to determine the interface or interface address.
329 modifier specifies that the
331 routing table entry is the
332 .Dq published (proxy-only)
334 entry, as reported by
337 All symbolic names specified for a
341 are looked up first as a host name using
342 .Xr gethostbyname 3 .
343 If this lookup fails,
345 is then used to interpret the name as that of a network.
352 modifiers may be used to specify the desired mpls label
353 operations for the route. Each route may have up to 3
354 label operations assigned to it. The label operations
355 may be combined between them, but specifically the
359 operations may be repeated if the intent is to push or pop
360 more than one label at once. The
362 operation always swaps the outer label and may not be
364 Here are some MPLS route examples:
366 Add an normal inet route, but push an mpls
370 .Bd -ragged -offset indent -compact
373 .Ar destination gateway
378 Add an normal inet route, but double-push an mpls
384 .Bd -ragged -offset indent -compact
387 .Ar destination gateway
394 Add an mpls route for an
398 and swap that label with
401 .Bd -ragged -offset indent -compact
414 utility uses a routing socket and the new message types
415 .Dv RTM_ADD , RTM_DELETE , RTM_GET ,
418 As such, only the super-user may modify
424 .It "add [host \&| network ] %s: gateway %s flags %x"
425 The specified route is being added to the tables. The
426 values printed are from the routing table entry supplied
430 If the gateway address used was not the primary address of the gateway
431 (the first one returned by
432 .Xr gethostbyname 3 ) ,
433 the gateway address is printed numerically as well as symbolically.
434 .It "delete [ host \&| network ] %s: gateway %s flags %x"
435 As above, but when deleting an entry.
439 command is specified, each routing table entry deleted
440 is indicated with a message of this form.
441 .It "Network is unreachable"
442 An attempt to add a route failed because the gateway listed was not
443 on a directly-connected network.
444 The next-hop gateway must be given.
446 A delete operation was attempted for an entry which
447 wasn't present in the tables.
448 .It "routing table overflow"
449 An add operation was attempted, but the system was
450 low on resources and was unable to allocate memory
451 to create the new entry.
452 .It "gateway uses the same route"
455 operation resulted in a route whose gateway uses the
456 same route as the one being changed.
457 The next-hop gateway should be reachable through a different route.
471 The first paragraph may have slightly exaggerated