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32 .\" @(#)route.8 8.3 (Berkeley) 3/19/94
33 .\" $FreeBSD: src/sbin/route/route.8,v 1.17.2.7 2001/10/02 10:04:01 ru Exp $
40 .Nd manually manipulate the routing tables
51 is a utility used to manually manipulate the network
52 routing tables. It normally is not needed, as a
53 system routing table management daemon such as
55 should tend to this task.
59 utility supports a limited number of general options,
60 but a rich command language, enabling the user to specify
61 any arbitrary request that could be delivered via the
62 programmatic interface discussed in
65 The following options are available:
66 .Bl -tag -width indent
68 Run in debug-only mode, i.e., do not actually modify the routing table.
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 Run in test-only mode.
78 is used instead of a socket.
80 (verbose) Print additional details.
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
147 .Ar destination gateway
153 is the destination host or network,
155 is the next-hop intermediary via which packets should be routed.
156 Routes to a particular host may be distinguished from those to
157 a network by interpreting the Internet address specified as the
160 The optional modifiers
164 force the destination to be interpreted as a network or a host, respectively.
168 .Dq local address part
174 is the symbolic name of a network, then the route is
175 assumed to be to a network; otherwise, it is presumed to be a
179 could also be specified in the
180 .Ar net Ns / Ns Ar bits
186 .Fl host Li 128.0.0.32 ;
189 .Fl host Li 128.32.0.130 ;
193 .Fl net Li 128.32.130
199 .Fl net Li 192.168.64 Fl netmask Li 255.255.240.0 .
207 which is the default route.
209 If the destination is directly reachable
210 via an interface requiring
211 no intermediary system to act as a gateway, the
213 modifier should be specified;
214 the gateway given is the address of this host on the common network,
215 indicating the interface to be used for transmission.
216 Alternately, if the interface is point to point the name of the interface
217 itself may be given, in which case the route remains valid even
218 if the local or remote addresses change.
220 For AF_INET and AF_INET6, the
222 modifier specifies the additional property of the route related to
223 the interface scope derived from interface
225 Such property allows for the presence of multiple route entries with
226 the same destination, where each route is associated with a unique
227 interface. This modifier is required in order to manipulate route
228 entries marked with the RTF_IFSCOPE flag.
230 The optional modifier
232 specify that all subsequent addresses
233 are specified as link-level addresses,
234 and the names must be numeric specifications rather than
240 to achieve the effect of an
243 redirect with the netmask option,
244 or to manually add subnet routes with
245 netmasks different from that of the implied network interface
246 (as would otherwise be communicated using the OSPF or ISIS routing protocols).
247 One specifies an additional ensuing address parameter
248 (to be interpreted as a network mask).
249 The implicit network mask generated in the AF_INET case
250 can be overridden by making sure this option follows the destination parameter.
257 is available instead of the
259 qualifier because non-continuous masks are not allowed in IPv6.
262 specifies network mask of
263 .Li ffff:ffff:0000:0000:0000:0000:0000:0000
265 The default value of prefixlen is 64 to get along with
266 the aggregatable address.
270 Note that the qualifier works only for
274 Routes have associated flags which influence operation of the protocols
275 when sending to destinations matched by the routes.
276 These flags may be set (or sometimes cleared)
277 by indicating the following corresponding modifiers:
279 -cloning RTF_CLONING - generates a new route on use
280 -xresolve RTF_XRESOLVE - emit mesg on use (for external lookup)
281 -iface ~RTF_GATEWAY - destination is directly reachable
282 -static RTF_STATIC - manually added route
283 -nostatic ~RTF_STATIC - pretend route added by kernel or daemon
284 -reject RTF_REJECT - emit an ICMP unreachable when matched
285 -blackhole RTF_BLACKHOLE - silently discard pkts (during updates)
286 -proto1 RTF_PROTO1 - set protocol specific routing flag #1
287 -proto2 RTF_PROTO2 - set protocol specific routing flag #2
288 -llinfo RTF_LLINFO - validly translates proto addr to link addr
291 The optional modifiers
301 provide initial values to quantities maintained in the routing entry
302 by transport level protocols, such as TCP or TP4.
303 These may be individually locked by preceding each such modifier to
307 meta-modifier, or one can
308 specify that all ensuing metrics may be locked by the
316 command where the destination and gateway are not sufficient to specify
319 case where several interfaces may have the
324 modifiers may be used to determine the interface or interface address.
328 modifier specifies that the
330 routing table entry is the
331 .Dq published (proxy-only)
333 entry, as reported by
336 All symbolic names specified for a
340 are looked up first as a host name using
341 .Xr gethostbyname 3 .
342 If this lookup fails,
344 is then used to interpret the name as that of a network.
347 uses a routing socket and the new message types
348 .Dv RTM_ADD , RTM_DELETE , RTM_GET ,
351 As such, only the super-user may modify
355 .It "add [host \&| network ] %s: gateway %s flags %x"
356 The specified route is being added to the tables. The
357 values printed are from the routing table entry supplied
361 If the gateway address used was not the primary address of the gateway
362 (the first one returned by
363 .Xr gethostbyname 3 ) ,
364 the gateway address is printed numerically as well as symbolically.
365 .It "delete [ host \&| network ] %s: gateway %s flags %x"
366 As above, but when deleting an entry.
370 command is specified, each routing table entry deleted
371 is indicated with a message of this form.
372 .It "Network is unreachable"
373 An attempt to add a route failed because the gateway listed was not
374 on a directly-connected network.
375 The next-hop gateway must be given.
377 A delete operation was attempted for an entry which
378 wasn't present in the tables.
379 .It "routing table overflow"
380 An add operation was attempted, but the system was
381 low on resources and was unable to allocate memory
382 to create the new entry.
383 .It "gateway uses the same route"
386 operation resulted in a route whose gateway uses the
387 same route as the one being changed.
388 The next-hop gateway should be reachable through a different route.
403 The first paragraph may have slightly exaggerated