xref: /freebsd/sbin/route/route.8 (revision 1e413cf93298b5b97441a21d9a50fdcd0ee9945e)
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28.\"     @(#)route.8	8.3 (Berkeley) 3/19/94
29.\" $FreeBSD$
30.\"
31.Dd October 2, 2005
32.Dt ROUTE 8
33.Os
34.Sh NAME
35.Nm route
36.Nd manually manipulate the routing tables
37.Sh SYNOPSIS
38.Nm
39.Op Fl dnqtv
40.Ar command
41.Oo
42.Op Ar modifiers
43.Ar args
44.Oc
45.Sh DESCRIPTION
46The
47.Nm
48utility is used to manually manipulate the network
49routing tables.
50It normally is not needed, as a
51system routing table management daemon, such as
52.Xr routed 8 ,
53should tend to this task.
54.Pp
55The
56.Nm
57utility supports a limited number of general options,
58but a rich command language, enabling the user to specify
59any arbitrary request that could be delivered via the
60programmatic interface discussed in
61.Xr route 4 .
62.Pp
63The following options are available:
64.Bl -tag -width indent
65.It Fl d
66Run in debug-only mode, i.e., do not actually modify the routing table.
67.It Fl n
68Bypass attempts to print host and network names symbolically
69when reporting actions.
70(The process of translating between symbolic
71names and numerical equivalents can be quite time consuming, and
72may require correct operation of the network; thus it may be expedient
73to forget this, especially when attempting to repair networking operations).
74.It Fl t
75Run in test-only mode.
76.Pa /dev/null
77is used instead of a socket.
78.It Fl v
79(verbose) Print additional details.
80.It Fl q
81Suppress all output from the
82.Cm add , change , delete ,
83and
84.Cm flush
85commands.
86.El
87.Pp
88The
89.Nm
90utility provides the following commands:
91.Pp
92.Bl -tag -width Fl -compact
93.It Cm add
94Add a route.
95.It Cm flush
96Remove all routes.
97.It Cm delete
98Delete a specific route.
99.It Cm del
100Another name for the
101.Cm delete
102command.
103.It Cm change
104Change aspects of a route (such as its gateway).
105.It Cm get
106Lookup and display the route for a destination.
107.It Cm monitor
108Continuously report any changes to the routing information base,
109routing lookup misses, or suspected network partitionings.
110.El
111.Pp
112The monitor command has the syntax:
113.Pp
114.Bd -ragged -offset indent -compact
115.Nm
116.Op Fl n
117.Cm monitor
118.Ed
119.Pp
120The flush command has the syntax:
121.Pp
122.Bd -ragged -offset indent -compact
123.Nm
124.Op Fl n
125.Cm flush
126.Op Ar family
127.Ed
128.Pp
129If the
130.Cm flush
131command is specified,
132.Nm
133will ``flush'' the routing tables of all gateway entries.
134When the address family may is specified by any of the
135.Fl osi ,
136.Fl xns ,
137.Fl atalk ,
138.Fl inet6 ,
139or
140.Fl inet
141modifiers, only routes having destinations with addresses in the
142delineated family will be deleted.
143.Pp
144The other commands have the following syntax:
145.Pp
146.Bd -ragged -offset indent -compact
147.Nm
148.Op Fl n
149.Ar command
150.Op Fl net No \&| Fl host
151.Ar destination gateway
152.Op Ar netmask
153.Ed
154.Pp
155where
156.Ar destination
157is the destination host or network,
158.Ar gateway
159is the next-hop intermediary via which packets should be routed.
160Routes to a particular host may be distinguished from those to
161a network by interpreting the Internet address specified as the
162.Ar destination
163argument.
164The optional modifiers
165.Fl net
166and
167.Fl host
168force the destination to be interpreted as a network or a host, respectively.
169Otherwise, if the
170.Ar destination
171has a
172.Dq local address part
173of
174INADDR_ANY
175.Pq Li 0.0.0.0 ,
176or if the
177.Ar destination
178is the symbolic name of a network, then the route is
179assumed to be to a network; otherwise, it is presumed to be a
180route to a host.
181Optionally, the
182.Ar destination
183could also be specified in the
184.Ar net Ns / Ns Ar bits
185format.
186.Pp
187For example,
188.Li 128.32
189is interpreted as
190.Fl host Li 128.0.0.32 ;
191.Li 128.32.130
192is interpreted as
193.Fl host Li 128.32.0.130 ;
194.Fl net Li 128.32
195is interpreted as
196.Li 128.32.0.0;
197.Fl net Li 128.32.130
198is interpreted as
199.Li 128.32.130.0;
200and
201.Li 192.168.64/20
202is interpreted as
203.Fl net Li 192.168.64 Fl netmask Li 255.255.240.0 .
204.Pp
205A
206.Ar destination
207of
208.Ar default
209is a synonym for
210.Fl net Li 0.0.0.0 ,
211which is the default route.
212.Pp
213If the destination is directly reachable
214via an interface requiring
215no intermediary system to act as a gateway, the
216.Fl interface
217modifier should be specified;
218the gateway given is the address of this host on the common network,
219indicating the interface to be used for transmission.
220Alternately, if the interface is point to point the name of the interface
221itself may be given, in which case the route remains valid even
222if the local or remote addresses change.
223.Pp
224The optional modifiers
225.Fl xns ,
226.Fl osi ,
227.Fl atalk ,
228and
229.Fl link
230specify that all subsequent addresses are in the
231.Tn XNS ,
232.Tn OSI ,
233or
234.Tn AppleTalk
235address families,
236or are specified as link-level addresses,
237and the names must be numeric specifications rather than
238symbolic names.
239.Pp
240The optional
241.Fl netmask
242modifier is intended
243to achieve the effect of an
244.Tn OSI
245.Tn ESIS
246redirect with the netmask option,
247or to manually add subnet routes with
248netmasks different from that of the implied network interface
249(as would otherwise be communicated using the OSPF or ISIS routing protocols).
250One specifies an additional ensuing address parameter
251(to be interpreted as a network mask).
252The implicit network mask generated in the AF_INET case
253can be overridden by making sure this option follows the destination parameter.
254.Pp
255For
256.Dv AF_INET6 ,
257the
258.Fl prefixlen
259qualifier
260is available instead of the
261.Fl mask
262qualifier because non-continuous masks are not allowed in IPv6.
263For example,
264.Fl prefixlen Li 32
265specifies network mask of
266.Li ffff:ffff:0000:0000:0000:0000:0000:0000
267to be used.
268The default value of prefixlen is 64 to get along with
269the aggregatable address.
270But 0 is assumed if
271.Cm default
272is specified.
273Note that the qualifier works only for
274.Dv AF_INET6
275address family.
276.Pp
277Routes have associated flags which influence operation of the protocols
278when sending to destinations matched by the routes.
279These flags may be set (or sometimes cleared)
280by indicating the following corresponding modifiers:
281.Bd -literal
282-cloning   RTF_CLONING    - generates a new route on use
283-xresolve  RTF_XRESOLVE   - emit mesg on use (for external lookup)
284-iface    ~RTF_GATEWAY    - destination is directly reachable
285-static    RTF_STATIC     - manually added route
286-nostatic ~RTF_STATIC     - pretend route added by kernel or daemon
287-reject    RTF_REJECT     - emit an ICMP unreachable when matched
288-blackhole RTF_BLACKHOLE  - silently discard pkts (during updates)
289-proto1    RTF_PROTO1     - set protocol specific routing flag #1
290-proto2    RTF_PROTO2     - set protocol specific routing flag #2
291-llinfo    RTF_LLINFO     - validly translates proto addr to link addr
292.Ed
293.Pp
294The optional modifiers
295.Fl rtt ,
296.Fl rttvar ,
297.Fl sendpipe ,
298.Fl recvpipe ,
299.Fl mtu ,
300.Fl hopcount ,
301.Fl expire ,
302and
303.Fl ssthresh
304provide initial values to quantities maintained in the routing entry
305by transport level protocols, such as TCP or TP4.
306These may be individually locked by preceding each such modifier to
307be locked by
308the
309.Fl lock
310meta-modifier, or one can
311specify that all ensuing metrics may be locked by the
312.Fl lockrest
313meta-modifier.
314.Pp
315In a
316.Cm change
317or
318.Cm add
319command where the destination and gateway are not sufficient to specify
320the route (as in the
321.Tn ISO
322case where several interfaces may have the
323same address), the
324.Fl ifp
325or
326.Fl ifa
327modifiers may be used to determine the interface or interface address.
328.Pp
329The optional
330.Fl proxy
331modifier specifies that the
332.Dv RTF_LLINFO
333routing table entry is the
334.Dq published (proxy-only)
335.Tn ARP
336entry, as reported by
337.Xr arp 8 .
338.Pp
339The optional
340.Fl genmask
341modifier specifies that a cloning mask is present.
342This specifies the mask applied when determining if a child route
343should be created.
344It is only applicable to network routes with the
345.Dv RTF_CLONING
346flag set.
347.Pp
348All symbolic names specified for a
349.Ar destination
350or
351.Ar gateway
352are looked up first as a host name using
353.Xr gethostbyname 3 .
354If this lookup fails,
355.Xr getnetbyname 3
356is then used to interpret the name as that of a network.
357.Pp
358The
359.Nm
360utility uses a routing socket and the new message types
361.Dv RTM_ADD , RTM_DELETE , RTM_GET ,
362and
363.Dv RTM_CHANGE .
364As such, only the super-user may modify
365the routing tables.
366.Sh EXIT STATUS
367.Ex -std
368.Sh DIAGNOSTICS
369.Bl -diag
370.It "add [host \&| network ] %s: gateway %s flags %x"
371The specified route is being added to the tables.
372The
373values printed are from the routing table entry supplied
374in the
375.Xr ioctl 2
376call.
377If the gateway address used was not the primary address of the gateway
378(the first one returned by
379.Xr gethostbyname 3 ) ,
380the gateway address is printed numerically as well as symbolically.
381.It "delete [ host \&| network ] %s: gateway %s flags %x"
382As above, but when deleting an entry.
383.It "%s %s done"
384When the
385.Cm flush
386command is specified, each routing table entry deleted
387is indicated with a message of this form.
388.It "Network is unreachable"
389An attempt to add a route failed because the gateway listed was not
390on a directly-connected network.
391The next-hop gateway must be given.
392.It "not in table"
393A delete operation was attempted for an entry which
394was not present in the tables.
395.It "routing table overflow"
396An add operation was attempted, but the system was
397low on resources and was unable to allocate memory
398to create the new entry.
399.It "gateway uses the same route"
400A
401.Cm change
402operation resulted in a route whose gateway uses the
403same route as the one being changed.
404The next-hop gateway should be reachable through a different route.
405.El
406.Sh SEE ALSO
407.\".Xr esis 4 ,
408.Xr netintro 4 ,
409.Xr route 4 ,
410.Xr arp 8 ,
411.Xr IPXrouted 8 ,
412.Xr routed 8
413.\".Xr XNSrouted 8
414.Sh HISTORY
415The
416.Nm
417utility appeared in
418.Bx 4.2 .
419.Sh BUGS
420The first paragraph may have slightly exaggerated
421.Xr routed 8 Ns 's
422abilities.
423.Pp
424Currently, routes with the
425.Dv RTF_BLACKHOLE
426flag set need to have the gateway set to an instance of the
427.Xr lo 4
428driver, using the
429.Fl iface
430option, for the flag to have any effect; unless IP fast forwarding
431is enabled, in which case the meaning of the flag will always
432be honored.
433