route8

Usage

Overview

At system start, routing tables are initialised and configured by netstart(8). The route utility can be used to view or manually manipulate the network routing tables. Only the superuser may modify the routing tables.

The options are as follows:

-d

Run in debug-only mode, i.e. don't actually modify the routing table.

-n

Bypass attempts to print host and network names symbolically when reporting actions. The process of translating between symbolic names and numerical equivalents can be quite time consuming, and may require correct operation of the network; thus it may be expedient to forgo this, especially when attempting to repair networking operations.

-q

Suppress all output.

-T rtable

Select an alternate routing table to modify or query. The default is to use the current routing table. The current routing table can be displayed with id(1).

-t

Write routing messages to a fake device (/dev/null) instead of a real routing socket to test route manipulation.

-v

Print additional details.

The commands are as follows:

route [-dnqtv] [-T rtable] add [modifier] destination gateway

route [-dnqtv] [-T rtable] change [modifier] destination gateway Add a new route, or modify an existing route, to the host or network at destination. gateway is the next-hop intermediary by which packets should be routed. See Address notation and interpretation for more information.

A number of modifiers can be used with add and change, and as documented with the other commands:

flags

Various flags can be set on routes (viewable using show):

-blackhole

silently discard packets

-cloning

generates a new route on use

-iface

destination is directly reachable

-llinfo

validly translates address to link address

-mpath

multiple gateways for a destination exist

-nostatic

pretend route added by kernel or daemon

-proto1

sets protocol specific routing flag #1

-proto2

sets protocol specific routing flag #2

-reject

emits an ICMP unreachable when matched

-static

manually added route (default)

The -blackhole and -reject flags require a gateway to the loopback interface, either 127.0.0.1 or ::1.

[-lock | -lockrest] -expire n

[-lock | -lockrest] -mtu n

Specify the lifetime for the route (e.g. if generated by a redirect) or the Maximum Transmission Unit (MTU) size for this path, respectively. The value n is locked if preceded by -lock; if preceded by -lockrest all following -expire and -mtu metrics are locked.

-host | -net

Interpret destination as a host or network, respectively.

-ifa address

-ifp ifname

Where the destination and gateway are not sufficient to specify the route, these modifiers may be used to determine the interface address (-ifa) or name (-ifp).

-label label

Associate the route with a label. Route labels can be used to attach arbitrary information to a route.

-mpath

Used to enter multiple gateways for the same destination address (multipath). When multiple routes exist for a destination, one route is selected based on the source address of the packet. The sysctl(8) variables net.inet.ip.multipath and net.inet6.ip6.multipath are used to control multipath routing. If set to 1, multiple routes with the same priority are used equally; if set to 0, the first route selected will be used for subsequent packets to that destination regardless of source.

-mplslabel -in label -push|-pop|-swap [-out label] For MPLS routes, specify an ingress LSR to associate a particular label to an IPv4/IPv6 route. The MPLS traffic -in and -out modifiers are intended to identify the ingress label and, optionally, the outgoing one. Additionally, one of the following operations must be used: -push, -pop or -swap. The route's gateway can be specified using the -inet or -inet6 modifier before the address.

-netmask mask

-prefixlen len

Used to add subnet routes with the specified netmask. The netmask should be specified after the destination parameter. If no netmask is specified, an implicit one is used for the AF_INET family. The network mask can also be specified as a prefix length, but in that case one of either -inet or -inet6 must also be specified.

-priority n

Specifies a routing priority. If no priority is specified, the kernel will set a priority depending on the RTF_STATIC flag to either RTP_STATIC or RTP_DEFAULT. Note that priority 1 is reserved for kernel use.

route [-dnqtv] [-T rtable] del[ete] destination [-priority n] [gateway] Delete the route to destination. If multiple routes to the destination exist, a specific route must be selected by specifying the priority and/or a gateway.

route [-T rtable] exec command [arg ...] Execute a command, forcing the process and its children to use the routing table and appropriate routing domain as specified with the -T rtable option.

route [-nqv] [-T rtable] flush [family] [-iface ifname] [-priority n] Delete all gateway entries from the routing table, optionally limited to a specific address family. Routes matching a specific interface or priority can be flushed by using the -iface or -priority modifiers.

route [-nv] [-T rtable] get destination [-priority n] [gateway] Display the route to destination. If multiple routes to the destination exist, a specific route may be selected by specifying the priority and/or a gateway.

route [-n] [-T rtable] monitor [family] [-iface] Continuously report any changes to the routing information base. The information reported can be limited to a specific address family, a specific routing table using the -T option, or interface specific messages (link state changes) using the -iface modifier.

route [-dtv] [-T rtable] nameserver interface [address ...] Broadcast a list of up to five nameserver address proposals to resolvd(8), which is used to update the list of nameservers for the given interface in resolv.conf(5). If no address is given, a request to remove the nameservers for the given interface is sent.

route [-nv] [-T rtable] show [family] [-gateway] [-label label] [-priority n] Display the routing table.

If -gateway is specified, only routes whose gateway are in the same address family as the destination are shown.

If -label is specified, only routes with the specified label are shown.

If -priority is specified, only routes with the specified priority are shown. It may be specified by number or one of local, connected, static, ospf, rip, or bgp. If the priority is negative, then routes that do not match the numeric priority are shown.

Within the output of show, the "Flags" column indicates what flags are set on the route. The mapping between letters and flags is:

1	RTF_PROTO1	Protocol specific routing flag #1.
2	RTF_PROTO2	Protocol specific routing flag #2.
3	RTF_PROTO3	Protocol specific routing flag #3.
B	RTF_BLACKHOLE	Just discard packets.
b	RTF_BROADCAST	Correspond to a local broadcast address.
C	RTF_CLONING	Generate new routes on use.
c	RTF_CLONED	Cloned routes (generated from RTF_CLONING).
D	RTF_DYNAMIC	Created dynamically (by redirect).
G	RTF_GATEWAY	Dest requires forwarding by intermediary.
H	RTF_HOST	Host entry (net otherwise).
h	RTF_CACHED	Referenced by gateway route.
L	RTF_LLINFO	Valid protocol to link address translation.
l	RTF_LOCAL	Correspond to a local address.
M	RTF_MODIFIED	Modified dynamically (by redirect).
m	RTF_MULTICAST	Correspond to a multicast address.
n	RTF_CONNECTED	Interface route.
P	RTF_MPATH	Multipath route.
R	RTF_REJECT	Host or net unreachable.
S	RTF_STATIC	Manually added.
T	RTF_MPLS	MPLS route.
U	RTF_UP	Route usable.

route [-T rtable] sourceaddr [-ifp ifname | address] Set the preferred source address to address. The source address can be set to the address assigned to interface ifname if -ifp is specified, or reset by setting the address to zero. If no arguments are given, the preferred source addresses are printed. The preferred source address is not used if the destination is on-link or the source address is assigned to a disabled interface.

Files

/etc/hosts

host and network name database

/etc/mygate

default gateway address

Exit status

For commands other than exec, the route utility exits 0 on success, and >0 if an error occurs.

For the exec command the route utility exits with the exit status of command if it could be invoked. Otherwise the route utility exits with one of the following values:

1

An invalid command line option was passed to route or setting the routing table failed.

126

command was found but could not be invoked.

127

command could not be found.

Examples

Show the current IPv4 routing tables, without attempting to print hostnames symbolically:

$ route -n show -inet

Add a static inet(4) route to the 192.168.5.0/24 network via the 192.168.0.1 gateway:

# route add -inet 192.168.5.0/24 192.168.0.1

Amend the inet(4) route to the 192.168.5.0/24 network to use the 192.168.0.2 gateway:

# route change -inet 192.168.5.0/24 192.168.0.2

Delete the inet(4) route to the 192.168.5.0/24 network:

# route delete -inet 192.168.5.0/24

Add a static inet6(4) route to a host which is on the vio0 interface that is outside your prefix, and use that host as a default gateway, as used by some hosting providers:

# route add -inet6 2001:db8:efef::1 -cloning -link -iface vio0

# route add -inet6 default 2001:db8:efef::1

Diagnostics

%s: gateway %s flags %x

The specified route is being added to or deleted from the tables. If the gateway address used was not the primary address of the gateway (the first one returned by gethostbyname(3)), the gateway address is printed numerically as well as symbolically.

%s %s done

When the flush command is specified, each routing table entry deleted is indicated with a message of this form.

Network is unreachable

An attempt to add a route failed because the gateway listed was not on a directly connected network. The next-hop gateway must be given.

not in table

A delete operation was attempted for an entry which wasn't present in the tables.

routing table overflow

An add operation was attempted, but the system was low on resources and was unable to allocate memory to create the new entry.