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route(1M)Name | Synopsis | Description | Options | Operands | Files | Attributes | See Also | Diagnostics | Notes Name
Synopsisroute [-fnvq] sub-command [ [modifiers] args]
route [-fnvq] [-p [-R root-dir]] add | delete [modifiers] destination gateway
[args]
route [-fnvq] change | get [modifiers] destination
[gateway [args]]
route [-fn] monitor [modifiers] route [-fnvq] flush [modifiers] route -p [-R root-dir] show Descriptionroute manually manipulates the network routing tables. These tables are normally maintained by the system routing daemon, such as in.routed(1M) and in.ripngd(1M). route supports a limited number of general options, but a rich command language. Users can specify an arbitrary request that can be delivered by means of the programmatic interface discussed in route(7P). route uses a routing socket and the new message types RTM_ADD, RTM_DELETE, RTM_GET, and RTM_CHANGE. While only superusers can modify routing tables, the RTM_GET operation is allowed for non-privileged users. Options
SubcommandsThe following subcommands are supported: The add and delete sub-commands have the following syntax:
where cmd is add or delete, destination is the destination host or network, and gateway is the next-hop intermediary through which packets should be routed. Modifiers described in OPERANDS can be placed anywhere on the command line. The get and change sub-commands have the following syntax:
where cmd is get or change, destination is the destination host or network, and gateway is the next-hop intermediary through which packets should be routed. Modifiers described in OPERANDS can be placed anywhere on the command line. The monitor sub-command has the following syntax:
Operands
route executes its sub-commands on routes to destinations by way of gateways. Destinations and GatewaysBy default, destination and gateway addresses are interpreted as IPv4 addresses. All symbolic names are tried first as a host name, using getipnodebyname(3SOCKET). If this lookup fails in the AF_INET case, getnetbyname(3SOCKET) interprets the name as that of a network. Including an optional modifier on the command line before the address changes how the route sub-command interprets it. The following modifiers are supported: For IPv4 addresses, routes to a particular host are by default distinguished from those to a network by interpreting the Internet address specified as the destination. If the destination has a local address part (that is, the portion not covered by the netmask) of 0, or if the destination is resolved as the symbolic name of a network, then the route is assumed to be to a network; otherwise, it is presumed to be a route to a host. You can force this selection by using one of the following modifiers: For example:
Two modifiers avoid confusion between addresses and keywords (for example., host used as a symbolic host name). You can distinguish a destination by preceding it with the -dst modifier. You can distinguish a gateway address by using the -gateway modifier. If the destination is directly reachable by way of an interface requiring no intermediary IP router to act as a gateway, this can be indicated by using the -interface or -iface modifier. In the following example, the route does not refer to an external gateway (router), but rather to one of the machine's interfaces. Packets with IP destination addresses matching the destination and mask on such a route are sent out on the interface identified by the gateway address. For interfaces using the ARP protocol, this type of route is used to specify that all matching destinations are local to the physical link. That is, a host could be configured to ARP for all addresses, without regard to the configured interface netmask, by adding a default route using this command. For example:
where gateway address hostname is the name or IP address associated with the network interface over which all matching packets should be sent. On a host with a single network interface, hostname is usually the same as the nodename returned by the uname -n command. See uname(1). For backward compatibility with older systems, directly reachable routes can also be specified by placing a 0 after the gateway address:
This value was once a route metric, but this metric is no longer used. If the value is specified as 0, then the destination is directly reachable (equivalent to specifying -interface). If it is non-zero but cannot be interpreted as a subnet mask, then a gateway is used (default). With the AF_INET address family or an IPv4 address, a separate subnet mask can be specified. This can be specified in one of the following ways: If a subnet mask is not specified, the mask used is the subnet mask of the output interface selected by the gateway address, if the classful network of the destination is the same as the classful network of the interface. Otherwise, the classful network mask for the destination address is used. Each of the following examples creates an IPv4 route to the destination 192.0.2.32 subnet with a subnet mask of 255.255.255.224:
For IPv6, only the slash format is accepted. The following example creates an IPv6 route to the destination 33fe:: with a netmask of 16 one-bits followed by 112 zero-bits.
In cases where the gateway does not uniquely identify the output interface (for example, when several interfaces have the same address), you can use the -ifp ifname modifier to specify the interface by name. For example, -ifp lo0 associates the route with the lo0 interface. If the named interface is an underlying interface in an IPMP (IP multipathing) group, then requests to add a route will automatically be translated to the corresponding IPMP IP interface, and requests to delete or change a route on an underlying interface will fail. Routing FlagsRoutes have associated flags that influence operation of the protocols when sending to destinations matched by the routes. These flags can be set (and in some cases cleared, indicated by ~) by including the following modifiers on the command line:
The optional modifiers -rtt, -rttvar, -sendpipe, -recvpipe, -mtu, -hopcount, -expire, and -ssthresh provide initial values to quantities maintained in the routing entry by transport level protocols, such as TCP. These can be individually locked either by preceding each modifier to be locked by the -lock meta-modifier, or by specifying that all ensuing metrics can be locked by the -lockrest meta-modifier. Some transport layer protocols can support only some of these metrics. The following optional modifiers are supported: CompatibilityThe modifiers host and net are taken to be equivalent to -host and -net. To specify a symbolic address that matches one of these names, use the dst or gateway keyword to distinguish it. For example: -dst host The following two flags are also accepted for compatibility with older systems, but have no effect.
The -ifa hostname modifier is also accepted, but has no effect. Files
AttributesSee attributes(5) for descriptions of the following attributes:
See Alsouname(1), in.ripngd(1M), in.routed(1M), netstat(1M), routed(1M), ioctl(2), getipnodebyname(3SOCKET), getnetbyname(3SOCKET), inet_addr(3SOCKET), defaultrouter(4), hosts(4), networks(4), attributes(5), arp(7P), ip(7P), route(7P), routing(7P) Diagnostics
NotesSpecifying that destinations are local (with the -interfacemodifier) assumes that the routers implement proxy ARP, meaning that they respond to ARP queries for all reachable destinations. Normally, using either router discovery or RIP is more reliable and scalable than using proxy ARP. See in.routed(1M) for information related to RIP. Combining the all destinations are local route with subnet or network routes can lead to unpredictable results. The search order as it relates to the all destinations are local route are undefined and can vary from release to release. Name | Synopsis | Description | Options | Operands | Files | Attributes | See Also | Diagnostics | Notes |
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