1.\" Copyright (c) 1983, 1991, 1993 2.\" The Regents of the University of California. All rights reserved. 3.\" 4.\" Redistribution and use in source and binary forms, with or without 5.\" modification, are permitted provided that the following conditions 6.\" are met: 7.\" 1. Redistributions of source code must retain the above copyright 8.\" notice, this list of conditions and the following disclaimer. 9.\" 2. Redistributions in binary form must reproduce the above copyright 10.\" notice, this list of conditions and the following disclaimer in the 11.\" documentation and/or other materials provided with the distribution. 12.\" 4. Neither the name of the University nor the names of its contributors 13.\" may be used to endorse or promote products derived from this software 14.\" without specific prior written permission. 15.\" 16.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 17.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 18.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 19.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 20.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 21.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 22.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 23.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 24.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 25.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 26.\" SUCH DAMAGE. 27.\" 28.\" @(#)route.8 8.3 (Berkeley) 3/19/94 29.\" $FreeBSD$ 30.\" 31.Dd March 24, 2012 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.It Cm show 111Another name for the 112.Cm get 113command. 114.El 115.Pp 116The monitor command has the syntax: 117.Pp 118.Bd -ragged -offset indent -compact 119.Nm 120.Op Fl n 121.Cm monitor 122.Ed 123.Pp 124The flush command has the syntax: 125.Pp 126.Bd -ragged -offset indent -compact 127.Nm 128.Op Fl n 129.Cm flush 130.Op Ar family 131.Ed 132.Pp 133If the 134.Cm flush 135command is specified, 136.Nm 137will ``flush'' the routing tables of all gateway entries. 138When the address family may is specified by any of the 139.Fl osi , 140.Fl xns , 141.Fl atalk , 142.Fl inet6 , 143or 144.Fl inet 145modifiers, only routes having destinations with addresses in the 146delineated family will be deleted. 147.Pp 148The other commands have the following syntax: 149.Pp 150.Bd -ragged -offset indent -compact 151.Nm 152.Op Fl n 153.Ar command 154.Op Fl net No \&| Fl host 155.Ar destination gateway 156.Op Ar netmask 157.Ed 158.Pp 159where 160.Ar destination 161is the destination host or network, 162.Ar gateway 163is the next-hop intermediary via which packets should be routed. 164Routes to a particular host may be distinguished from those to 165a network by interpreting the Internet address specified as the 166.Ar destination 167argument. 168The optional modifiers 169.Fl net 170and 171.Fl host 172force the destination to be interpreted as a network or a host, respectively. 173Otherwise, if the 174.Ar destination 175has a 176.Dq local address part 177of 178INADDR_ANY 179.Pq Li 0.0.0.0 , 180or if the 181.Ar destination 182is the symbolic name of a network, then the route is 183assumed to be to a network; otherwise, it is presumed to be a 184route to a host. 185Optionally, the 186.Ar destination 187could also be specified in the 188.Ar net Ns / Ns Ar bits 189format. 190.Pp 191For example, 192.Li 128.32 193is interpreted as 194.Fl host Li 128.0.0.32 ; 195.Li 128.32.130 196is interpreted as 197.Fl host Li 128.32.0.130 ; 198.Fl net Li 128.32 199is interpreted as 200.Li 128.32.0.0; 201.Fl net Li 128.32.130 202is interpreted as 203.Li 128.32.130.0; 204and 205.Li 192.168.64/20 206is interpreted as 207.Fl net Li 192.168.64 Fl netmask Li 255.255.240.0 . 208.Pp 209A 210.Ar destination 211of 212.Ar default 213is a synonym for 214.Fl net Li 0.0.0.0 , 215which is the default route. 216.Pp 217If the destination is directly reachable 218via an interface requiring 219no intermediary system to act as a gateway, the 220.Fl interface 221modifier should be specified; 222the gateway given is the address of this host on the common network, 223indicating the interface to be used for transmission. 224Alternately, if the interface is point to point the name of the interface 225itself may be given, in which case the route remains valid even 226if the local or remote addresses change. 227.Pp 228The optional modifiers 229.Fl xns , 230.Fl osi , 231.Fl atalk , 232and 233.Fl link 234specify that all subsequent addresses are in the 235.Tn XNS , 236.Tn OSI , 237or 238.Tn AppleTalk 239address families, 240or are specified as link-level addresses, 241and the names must be numeric specifications rather than 242symbolic names. 243.Pp 244The optional 245.Fl netmask 246modifier is intended 247to achieve the effect of an 248.Tn OSI 249.Tn ESIS 250redirect with the netmask option, 251or to manually add subnet routes with 252netmasks different from that of the implied network interface 253(as would otherwise be communicated using the OSPF or ISIS routing protocols). 254One specifies an additional ensuing address parameter 255(to be interpreted as a network mask). 256The implicit network mask generated in the AF_INET case 257can be overridden by making sure this option follows the destination parameter. 258.Pp 259For 260.Dv AF_INET6 , 261the 262.Fl prefixlen 263qualifier 264is available instead of the 265.Fl mask 266qualifier because non-continuous masks are not allowed in IPv6. 267For example, 268.Fl prefixlen Li 32 269specifies network mask of 270.Li ffff:ffff:0000:0000:0000:0000:0000:0000 271to be used. 272The default value of prefixlen is 64 to get along with 273the aggregatable address. 274But 0 is assumed if 275.Cm default 276is specified. 277Note that the qualifier works only for 278.Dv AF_INET6 279address family. 280.Pp 281Routes have associated flags which influence operation of the protocols 282when sending to destinations matched by the routes. 283These flags may be set (or sometimes cleared) 284by indicating the following corresponding modifiers: 285.Bd -literal 286-xresolve RTF_XRESOLVE - emit mesg on use (for external lookup) 287-iface ~RTF_GATEWAY - destination is directly reachable 288-static RTF_STATIC - manually added route 289-nostatic ~RTF_STATIC - pretend route added by kernel or daemon 290-reject RTF_REJECT - emit an ICMP unreachable when matched 291-blackhole RTF_BLACKHOLE - silently discard pkts (during updates) 292-proto1 RTF_PROTO1 - set protocol specific routing flag #1 293-proto2 RTF_PROTO2 - set protocol specific routing flag #2 294.Ed 295.Pp 296The optional modifiers 297.Fl rtt , 298.Fl rttvar , 299.Fl sendpipe , 300.Fl recvpipe , 301.Fl mtu , 302.Fl hopcount , 303.Fl expire , 304and 305.Fl ssthresh 306provide initial values to quantities maintained in the routing entry 307by transport level protocols, such as TCP or TP4. 308These may be individually locked by preceding each such modifier to 309be locked by 310the 311.Fl lock 312meta-modifier, or one can 313specify that all ensuing metrics may be locked by the 314.Fl lockrest 315meta-modifier. 316.Pp 317In a 318.Cm change 319or 320.Cm add 321command where the destination and gateway are not sufficient to specify 322the route (as in the 323.Tn ISO 324case where several interfaces may have the 325same address), the 326.Fl ifp 327or 328.Fl ifa 329modifiers may be used to determine the interface or interface address. 330.Pp 331All symbolic names specified for a 332.Ar destination 333or 334.Ar gateway 335are looked up first as a host name using 336.Xr gethostbyname 3 . 337If this lookup fails, 338.Xr getnetbyname 3 339is then used to interpret the name as that of a network. 340.Pp 341The 342.Nm 343utility uses a routing socket and the new message types 344.Dv RTM_ADD , RTM_DELETE , RTM_GET , 345and 346.Dv RTM_CHANGE . 347As such, only the super-user may modify 348the routing tables. 349.Sh EXIT STATUS 350.Ex -std 351.Sh EXAMPLES 352Add a default route to the network routing table. 353This will send all packets for destinations not available in the routing table 354to the default gateway at 192.168.1.1: 355.Pp 356.Dl route add -net 0.0.0.0/0 192.168.1.1 357.Pp 358A shorter version of adding a default route can also be written as: 359.Pp 360.Dl route add default 192.168.1.1 361.Pp 362Add a static route to the 172.16.10.0/24 network via the 172.16.1.1 gateway: 363.Pp 364.Dl route add -net 172.16.10.0/24 172.16.1.1 365.Pp 366Change the gateway of an already established static route in the routing table: 367.Pp 368.Dl route change -net 172.16.10.0/24 172.16.1.2 369.Pp 370Display the route for a destination network: 371.Pp 372.Dl route show 172.16.10.0 373.Pp 374Delete a static route from the routing table: 375.Pp 376.Dl route delete -net 172.16.10.0/24 172.16.1.2 377.Pp 378Remove all routes from the routing table: 379.Pp 380.Dl route flush 381.Sh DIAGNOSTICS 382.Bl -diag 383.It "add [host \&| network ] %s: gateway %s flags %x" 384The specified route is being added to the tables. 385The 386values printed are from the routing table entry supplied 387in the 388.Xr ioctl 2 389call. 390If the gateway address used was not the primary address of the gateway 391(the first one returned by 392.Xr gethostbyname 3 ) , 393the gateway address is printed numerically as well as symbolically. 394.It "delete [ host \&| network ] %s: gateway %s flags %x" 395As above, but when deleting an entry. 396.It "%s %s done" 397When the 398.Cm flush 399command is specified, each routing table entry deleted 400is indicated with a message of this form. 401.It "Network is unreachable" 402An attempt to add a route failed because the gateway listed was not 403on a directly-connected network. 404The next-hop gateway must be given. 405.It "not in table" 406A delete operation was attempted for an entry which 407was not present in the tables. 408.It "routing table overflow" 409An add operation was attempted, but the system was 410low on resources and was unable to allocate memory 411to create the new entry. 412.It "gateway uses the same route" 413A 414.Cm change 415operation resulted in a route whose gateway uses the 416same route as the one being changed. 417The next-hop gateway should be reachable through a different route. 418.El 419.Sh SEE ALSO 420.\".Xr esis 4 , 421.Xr netintro 4 , 422.Xr route 4 , 423.Xr arp 8 , 424.Xr IPXrouted 8 , 425.Xr routed 8 426.\".Xr XNSrouted 8 427.Sh HISTORY 428The 429.Nm 430utility appeared in 431.Bx 4.2 . 432.Sh BUGS 433The first paragraph may have slightly exaggerated 434.Xr routed 8 Ns 's 435abilities. 436.Pp 437Currently, routes with the 438.Dv RTF_BLACKHOLE 439flag set need to have the gateway set to an instance of the 440.Xr lo 4 441driver, using the 442.Fl iface 443option, for the flag to have any effect; unless IP fast forwarding 444is enabled, in which case the meaning of the flag will always 445be honored. 446