path: root/sbin/ifconfig/ifconfig.8

.\"	$OpenBSD: ifconfig.8,v 1.227 2012/03/18 23:37:08 jmc Exp $
.\"	$NetBSD: ifconfig.8,v 1.11 1996/01/04 21:27:29 pk Exp $
.\"     $FreeBSD: ifconfig.8,v 1.16 1998/02/01 07:03:29 steve Exp $
.\"
.\" Copyright (c) 1983, 1991, 1993
.\"	The Regents of the University of California.  All rights reserved.
.\"
.\" Redistribution and use in source and binary forms, with or without
.\" modification, are permitted provided that the following conditions
.\" are met:
.\" 1. Redistributions of source code must retain the above copyright
.\"    notice, this list of conditions and the following disclaimer.
.\" 2. Redistributions in binary form must reproduce the above copyright
.\"    notice, this list of conditions and the following disclaimer in the
.\"    documentation and/or other materials provided with the distribution.
.\" 3. Neither the name of the University nor the names of its contributors
.\"    may be used to endorse or promote products derived from this software
.\"    without specific prior written permission.
.\"
.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
.\" ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
.\" SUCH DAMAGE.
.\"
.\"     @(#)ifconfig.8	8.4 (Berkeley) 6/1/94
.\"
.Dd $Mdocdate: March 18 2012 $
.Dt IFCONFIG 8
.Os
.Sh NAME
.Nm ifconfig
.Nd configure network interface parameters
.Sh SYNOPSIS
.Nm ifconfig
.Op Fl AaC
.Op Ar interface
.Op Ar address_family
.Oo
.Ar address
.Op Ar dest_address
.Oc
.Op Ar parameters
.Sh DESCRIPTION
The
.Nm
utility is used to assign an address
to a network interface and/or configure
network interface parameters.
Generally speaking,
.Xr hostname.if 5
files are used at boot-time to define the network address
of each interface present on a machine;
.Nm
is used at
a later time to redefine an interface's address
or other operating parameters.
.Pp
.Nm
displays the current configuration for a network interface
when no optional parameters are supplied.
If a protocol family is specified,
.Nm
will report only the details specific to that protocol family.
If no parameters are provided, a summary of all interfaces is provided.
.Pp
Only the superuser may modify the configuration of a network interface.
.Pp
The following options are available:
.Bl -tag -width Ds
.It Fl A
Causes full interface alias information for each interface to
be displayed.
.It Fl a
Causes
.Nm
to print information on all interfaces.
The protocol family may be specified as well.
This is the default, if no parameters are given to
.Nm .
.It Fl C
Print the names of all network pseudo-devices that
can be created dynamically at runtime using
.Cm ifconfig create .
.It Ar interface
The
.Ar interface
parameter is a string of the form
.Dq name unit ,
for example,
.Dq en0 .
If no optional parameters are supplied, this string can instead be just
.Dq name .
If an interface group of that name exists, all interfaces in the group
will be shown.
Otherwise all interfaces of the same type will be displayed
(for example,
.Dq fxp
will display all
.Xr fxp 4
interfaces).
.It Ar address_family
Specifies the address family
which affects interpretation of the remaining parameters.
Since an interface can receive transmissions in differing protocols
with different naming schemes, specifying the address family is recommended.
The address or protocol families currently
supported are
.Dq inet
and
.Dq inet6 .
.It Ar address
Internet version 4 and 6 addresses
take the form of
a host name present in the host name database,
.Xr hosts 5 ;
.Dq dot
notation (IPv4);
colon separated (IPv6);
or CIDR notation.
.It Ar dest_address
Specify the address of the correspondent on the other end
of a point-to-point link.
.El
.Pp
The following
.Ar parameters
may be set with
.Nm :
.Bl -tag -width dest_addressxx
.It Cm alias
Establish an additional network address for this interface.
This is sometimes useful when changing network numbers, and
one wishes to accept packets addressed to the old interface.
.It Fl alias
A synonym for
.Cm delete .
Use of this option is discouraged in favour of
.Cm delete .
.It Cm arp
Enable the use of the Address Resolution Protocol (ARP)
in mapping
between network level addresses and link level addresses (default).
This is currently implemented for mapping between
DARPA Internet addresses and Ethernet addresses.
.It Fl arp
Disable the use of ARP.
.It Cm broadcast Ar addr
(inet only)
Specify the address to use to represent broadcasts to the
network.
The default broadcast address is the address with a host part of all 1's.
.It Cm create
Create the specified network pseudo-device.
At least the following devices can be created on demand:
.Pp
.Xr bridge 4 ,
.Xr carp 4 ,
.Xr enc 4 ,
.Xr faith 4 ,
.Xr gif 4 ,
.Xr gre 4 ,
.Xr lo 4 ,
.Xr mpe 4 ,
.Xr pflog 4 ,
.Xr pflow 4 ,
.Xr pfsync 4 ,
.Xr ppp 4 ,
.Xr pppoe 4 ,
.Xr sl 4 ,
.Xr trunk 4 ,
.Xr tun 4 ,
.Xr vether 4 ,
.Xr vlan 4
.It Cm debug
Enable driver-dependent debugging code; usually, this turns on
extra console error logging.
.It Fl debug
Disable driver-dependent debugging code.
.It Cm delete
Remove the specified network address,
including any netmask or destination address configured with this address.
.It Cm description Ar value
Specify a description of the interface.
This can be used to label interfaces in situations where they may
otherwise be difficult to distinguish.
.It Cm -description
Clear the interface description.
.It Cm destroy
Destroy the specified network pseudo-device.
.It Cm down
Mark an interface
.Dq down .
When an interface is marked
.Dq down ,
the system will not attempt to
transmit messages through that interface.
If possible, the interface will be reset to disable reception as well.
This action automatically disables routes using the interface.
.It Cm group Ar group-name
Assign the interface to a
.Dq group .
.Ar group-name
may not be longer than 15 characters and must not end with a digit.
Any interface can be in multiple groups.
.Pp
For instance, a group could be used to create a hardware independent
.Xr pf 4
ruleset (i.e. not one based on the names of NICs) using
existing (egress, carp, etc.) or user-defined groups.
.Pp
Some interfaces belong to specific groups by default:
.Pp
.Bl -dash -width Ds -compact
.It
All interfaces are members of the
.Em all
interface group.
.It
Cloned interfaces are members of their interface family group.
For example, a PPP interface such as
.Em ppp0
is a member of the
.Em ppp
interface family group.
.It
The interface(s) the default route(s) point to are members of the
.Em egress
interface group.
.It
IEEE 802.11 wireless interfaces are members of the
.Em wlan
interface group.
.It
Any interfaces used for network booting are members of the
.Em netboot
interface group.
.El
.It Cm -group Ar group-name
Remove the interface from the given
.Dq group .
.It Cm hwfeatures
Display the interface hardware features:
.Pp
.Bl -tag -width 14n -offset indent -compact
.It Sy CSUM_IPv4
The device supports IPv4 checksum offload.
.It Sy CSUM_TCPv4
As above, for TCP in IPv4 datagrams.
.It Sy CSUM_UDPv4
As above, for UDP.
.It Sy VLAN_MTU
MTU can be configured on a per-vlan basis.
.It Sy VLAN_HWTAGGING
On transmit, the device can prepend the
.Xr vlan
tag.
.It Sy CSUM_TCPv6
As CSUM_TCPv4, but supports IPv6 datagrams.
.It Sy CSUM_UDPv6
As above, for UDP.
.It Sy WOL
The device supports Wake on LAN (WoL).
.El
.It Fl inet6
Disable
.Xr inet6 4
on the given interface and remove all configured
.Xr inet6 4
addresses, including the link-local ones.
To turn it on again, assign any inet6 address or run
.Xr rtsol 8 .
.It Cm instance Ar minst
Set the media instance to
.Ar minst .
This is useful for devices which have multiple physical layer interfaces
(PHYs).
Setting the instance on such devices may not be strictly required
by the network interface driver as the driver may take care of this
automatically; see the driver's manual page for more information.
.It Cm link[0-2]
Enable special processing of the link level of the interface.
These three options are interface specific in actual effect; however,
they are in general used to select special modes of operation.
An example
of this is to enable SLIP compression, or to select the connector type
for some Ethernet cards.
Refer to the man page for the specific driver for more information.
.It Fl link[0-2]
Disable special processing at the link level with the specified interface.
.It Cm lladdr Ar etheraddr Ns \*(Ba Ns Cm random
Change the link layer address (MAC address) of the interface.
This should be specified as six colon-separated hex values, or can
be chosen randomly.
.It Cm media Op Ar type
Set the media type of the interface to
.Ar type .
If no argument is given,
display a list of all available media.
.Pp
Some interfaces support the mutually exclusive use of one of several
different physical media connectors.
For example, a 10Mb/s Ethernet interface might support the use of either
AUI or twisted pair connectors.
Setting the media type to
.Dq 10base5
or
.Dq AUI
would change the currently active connector to the AUI port.
Setting it to
.Dq 10baseT
or
.Dq UTP
would activate twisted pair.
Refer to the interface's driver-specific man page for a complete
list of the available types,
or use the following command
for a listing of choices:
.Pp
.Dl $ ifconfig interface media
.It Cm mediaopt Ar opts
Set the specified media options on the interface.
.Ar opts
is a comma delimited list of options to apply to the interface.
Refer to the interface's driver-specific man page for a complete
list of available options,
or use the following command
for a listing of choices:
.Pp
.Dl $ ifconfig interface media
.It Fl mediaopt Ar opts
Disable the specified media options on the interface.
.It Cm metric Ar nhops
Set the routing metric of the interface to
.Ar nhops ,
default 0.
The routing metric can be used by routing protocols.
Higher metrics have the effect of making a route less favorable.
.It Cm mode Ar mode
If the driver for the interface supports the media selection system,
set the specified operating mode on the interface to the given
.Ar mode .
For IEEE 802.11 wireless interfaces that support multiple operating modes,
this directive is used to select between 802.11a
.Pq Dq 11a ,
802.11b
.Pq Dq 11b ,
and 802.11g
.Pq Dq 11g
operating modes.
.It Cm mpls
Enable Multiprotocol Label Switching (MPLS) on the interface,
allowing it to send and receive MPLS traffic.
.It Fl mpls
Disable MPLS on the interface.
.It Cm mtu Ar value
Set the MTU for this device to the given
.Ar value .
Cloned routes will inherit this value as a default.
Currently, not all devices support setting the MTU.
.It Cm netmask Ar mask
(inet and inet6)
Specify how much of the address to reserve for subdividing
networks into subnetworks.
The mask includes the network part of the local address
and the subnet part, which is taken from the host field of the address.
The mask can be specified as a single hexadecimal number
with a leading 0x, with a dot-notation Internet address,
or with a pseudo-network name listed in the network table
.Xr networks 5 .
The mask contains 1's for the bit positions in the 32-bit address
which are to be used for the network and subnet parts,
and 0's for the host part.
The mask should contain at least the standard network portion,
and the subnet field should be contiguous with the network
portion.
.\" see
.\" Xr eon 5 .
.It Cm prefixlen Ar n
(inet and inet6 only)
Effect is similar to
.Cm netmask ,
but you can specify prefix length by digits.
.It Cm priority Ar n
Set the interface routing priority to
.Ar n .
This will influence the default routing priority of new static routes added to
the kernel.
.Ar n
is in the range of 0 to 16 with smaller numbers being better.
.It Cm rdomain Ar route-id
Attach the interface to the routing table with the specified
.Ar route-id .
Interfaces in different routing domains are separated and can not directly
pass traffic between each other.
By default all interfaces belong to routing table 0.
.It Cm rtlabel Ar route-label
(inet)
Attach
.Ar route-label
to new network routes of the specified interface.
Route labels can be used to implement policy routing;
see
.Xr route 4 ,
.Xr route 8 ,
and
.Xr pf.conf 5 .
.It Cm -rtlabel
Clear the route label.
.It Cm timeslot Ar timeslot_range
Set the timeslot range map, which is used to control which channels
an interface device uses.
.It Cm up
Mark an interface
.Dq up .
This may be used to enable an interface after an
.Cm ifconfig down .
It happens automatically when setting the first address on an interface.
If the interface was reset when previously marked down,
the hardware will be re-initialized.
.Pp
.It Cm wol
Enable Wake on LAN (WoL).
When enabled, reception of a WoL frame will cause the network card to
power up the system from standby or suspend mode.
WoL frames are sent using
.Xr arp 8 .
.It Fl wol
Disable WoL.
WoL is disabled at boot by the driver, if possible.
.El
.Pp
.Nm
supports a multitude of sub-types,
described in the following sections:
.Pp
.Bl -dash -offset indent -compact
.It
.Xr bridge 4
.It
.Xr carp 4
.It
IEEE 802.11 (wireless devices)
.It
.Xr inet6 4
.It
interface groups
.It
.Xr mpe 4
.It
.Xr pflow 4
.It
.Xr pfsync 4
.It
.Xr pppoe 4
.It
.Xr sppp 4
(PPP Link Control Protocol)
.It
.Xr trunk 4
.It
tunnel
.Pf ( Xr gif 4
and
.Xr gre 4 )
.It
.Xr vlan 4
.El
.\" BRIDGE
.Sh BRIDGE
The following options are available for a
.Xr bridge 4
interface:
.Bl -tag -width Ds
.It Cm add Ar interface
Add
.Ar interface
as a member of the bridge.
The interface is put into promiscuous mode so
that it can receive every packet sent on the
network.
An interface can be a member of at most one bridge.
.It Cm addr
Display the addresses that have been learned by the bridge.
.It Cm addspan Ar interface
Add
.Ar interface
as a span port on the bridge.
.It Cm autoedge Ar interface
Automatically detect the spanning tree edge port status on
.Ar interface .
This is the default for interfaces added to the bridge.
.It Cm -autoedge Ar interface
Disable automatic spanning tree edge port detection on
.Ar interface .
.It Cm autoptp Ar interface
Automatically detect the point-to-point status on
.Ar interface
by checking the full duplex link status.
This is the default for interfaces added to the bridge.
.It Cm -autoptp Ar interface
Disable automatic point-to-point link detection on
.Ar interface .
.It Cm blocknonip Ar interface
Mark
.Ar interface
so that no non-IPv4, IPv6, ARP, or Reverse
ARP packets are accepted from it or forwarded to it from other
bridge member interfaces.
.It Cm -blocknonip Ar interface
Allow non-IPv4, IPv6, ARP, or Reverse ARP packets through
.Ar interface .
.It Cm del Ar interface
Alias for
.Cm delete .
.It Cm deladdr Ar address
Delete
.Ar address
from the cache.
.It Cm delete Ar interface
Remove
.Ar interface
from the bridge.
Promiscuous mode is turned off for the interface when it is
removed from the bridge.
.It Cm delspan Ar interface
Delete
.Ar interface
from the list of span ports of the bridge.
.It Cm discover Ar interface
Mark
.Ar interface
so that packets are sent out of the interface
if the destination port of the packet is unknown.
If the bridge has no address cache entry for the destination of
a packet, meaning that there is no static entry and no dynamically learned
entry for the destination, the bridge will forward the packet to all member
interfaces that have this flag set.
This is the default for interfaces added to the bridge.
.It Cm -discover Ar interface
Mark
.Ar interface
so that packets are not sent out of the interface
if the destination port of the packet is unknown.
Turning this flag
off means that the bridge will not send packets out of this interface
unless the packet is a broadcast packet, multicast packet, or a
packet with a destination address found on the interface's segment.
This, in combination with static address cache entries,
prevents potentially sensitive packets from being sent on
segments that have no need to see the packet.
.It Cm down
Stop the bridge from forwarding packets.
.It Cm edge Ar interface
Set
.Ar interface
as a spanning tree edge port.
An edge port is a single connection to the network and cannot create
bridge loops.
This allows a straight transition to forwarding.
.It Cm -edge Ar interface
Disable edge port status on
.Ar interface .
.It Cm flush
Remove all dynamically learned addresses from the cache.
.It Cm flushall
Remove all addresses from the cache including static addresses.
.It Cm flushrule Ar interface
Remove all Ethernet MAC filtering rules from
.Ar interface .
.It Cm fwddelay Ar time
Set the time (in seconds) before an interface begins forwarding packets.
Defaults to 15 seconds, minimum of 4, maximum of 30.
.It Cm hellotime Ar time
Set the time (in seconds) between broadcasting spanning tree protocol
configuration packets.
Defaults to 2 seconds, minimum of 1, maximum of 2.
This option is only supported in STP mode with rapid transitions disabled;
see the
.Cm proto
command for setting the protocol version.
.It Cm holdcnt Ar time
Set the transmit hold count, which is the number of spanning tree protocol
packets transmitted before being rate limited.
Defaults to 6, minimum of 1, maximum of 10.
.It Cm ifcost Ar interface Ar num
Set the spanning tree path cost of
.Ar interface
to
.Ar num .
Defaults to 55, minimum of 1, maximum of 200000000 in RSTP mode,
and maximum of 65535 in STP mode.
.It Cm -ifcost Ar interface
Automatically calculate the spanning tree priority of
.Ar interface
based on the current link speed, interface status, and spanning tree mode.
This is the default for interfaces added to the bridge.
.It Cm ifpriority Ar interface Ar num
Set the spanning tree priority of
.Ar interface
to
.Ar num .
Defaults to 128, minimum of 0, maximum of 240.
.It Cm learn Ar interface
Mark
.Ar interface
so that the source address of packets received from
the interface
are entered into the address cache.
This is the default for interfaces added to the bridge.
.It Cm -learn Ar interface
Mark
.Ar interface
so that the source address of packets received from interface
are not entered into the address cache.
.It Cm link0
Setting this flag stops all IP multicast packets from
being forwarded by the bridge.
.It Cm -link0
Clear the
.Cm link0
flag on the bridge interface.
.It Cm link1
Setting this flag stops all non-IP multicast packets from
being forwarded by the bridge.
.It Cm -link1
Clear the
.Cm link1
flag on the bridge interface.
.It Cm link2
Setting this flag causes all packets to be passed on to
.Xr ipsec 4
for processing, based on the policies established by the administrator
using the
.Xr ipsecctl 8
command and
.Xr ipsec.conf 5 .
If appropriate security associations (SAs) exist, they will be used to
encrypt or decrypt the packets.
Otherwise, any key management daemons such as
.Xr isakmpd 8
that are running on the bridge will be invoked to establish the
necessary SAs.
These daemons have to be configured as if they were running on the
host whose traffic they are protecting (i.e. they need to have the
appropriate authentication and authorization material, such as keys
and certificates, to impersonate the protected host(s)).
.It Cm -link2
Clear the
.Cm link2
flag on the bridge interface.
.It Cm maxaddr Ar size
Set the address cache size to
.Ar size .
The default is 100 entries.
.It Cm maxage Ar time
Set the time (in seconds) that a spanning tree protocol configuration is valid.
Defaults to 20 seconds, minimum of 6, maximum of 40.
.It Cm proto Ar value
Force the spanning tree protocol version.
The available values are
.Ar rstp
to operate in the default Rapid Spanning Tree (RSTP) mode
or
.Ar stp
to force operation in Spanning Tree (STP) mode with rapid transitions disabled.
.It Cm ptp Ar interface
Set
.Ar interface
as a point-to-point link.
This is required for straight transitions to forwarding and
should be enabled for a full duplex link or a
.Xr trunk 4
with at least two physical links to the same network segment.
.It Cm -ptp Ar interface
Disable point-to-point link status on
.Ar interface .
This should be disabled for a half duplex link and for an interface
connected to a shared network segment,
like a hub or a wireless network.
.It Xo
.Cm rule
.Cm block Ns \*(Ba Ns Cm pass
.Op Cm in \*(Ba out
.Cm on Ar interface
.Op Cm src Ar address
.Op Cm dst Ar address
.Op Cm tag Ar tagname
.Xc
Add a filtering rule to an interface.
Rules have a similar syntax to those in
.Xr pf.conf 5 .
Rules can be used to selectively block or pass frames based on Ethernet
MAC addresses.
They can also tag packets for
.Xr pf 4
to filter on.
Rules are processed in the order in which they were added
to the interface, and the first rule matched takes the action (block or pass)
and, if given, the tag of the rule.
If no source or destination address is specified, the
rule will match all frames (good for creating a catchall policy).
.It Cm rulefile Ar filename
Load a set of rules from the file
.Ar filename .
.It Cm rules Ar interface
Display the active filtering rules in use on
.Ar interface .
.It Cm spanpriority Ar num
Set the spanning priority of this bridge to
.Ar num .
Defaults to 32768, minimum of 0, maximum of 61440.
.It Cm static Ar interface address
Add a static entry into the address cache pointing to
.Ar interface .
Static entries are never aged out of the cache or replaced, even if the address
is seen on a different interface.
.It Cm stp Ar interface
Enable spanning tree protocol on
.Ar interface .
.It Cm -stp Ar interface
Disable spanning tree protocol on
.Ar interface .
This is the default for interfaces added to the bridge.
.It Cm timeout Ar time
Set the timeout, in seconds, for addresses in the cache to
.Ar time .
The default is 240 seconds.
If
.Ar time
is set to zero, then entries will not be expired.
.It Cm up
Start the bridge forwarding packets.
.El
.\" CARP
.Sh CARP
.nr nS 1
.Bk -words
.Nm ifconfig
.Ar carp-interface
.Op Cm advbase Ar n
.Op Cm advskew Ar n
.Op Cm balancing Ar mode
.Op Cm carpnodes Ar vhid:advskew,vhid:advskew,...
.Op Cm carpdev Ar iface
.Op Oo Fl Oc Ns Cm carppeer Ar peer_address
.Op Cm pass Ar passphrase
.Op Cm state Ar state
.Op Cm vhid Ar host-id
.Ek
.nr nS 0
.Pp
The following options are available for a
.Xr carp 4
interface:
.Bl -tag -width Ds
.It Cm advbase Ar n
Set the base advertisement interval to
.Ar n
seconds.
This is an 8-bit number; the default value is 1 second.
.It Cm advskew Ar n
Skew the advertisement interval by
.Ar n .
This is an 8-bit number; the default value is 0.
.It Cm balancing Ar mode
Set the load balancing mode to
.Ar mode .
Valid modes are
.Ar arp ,
.Ar ip ,
.Ar ip-stealth ,
and
.Ar ip-unicast .
.It Cm carpnodes Ar vhid:advskew,vhid:advskew,...
Create a load balancing group consisting of up to 32 nodes.
Each node is specified as a
.Ar vhid:advskew
tuple in a comma separated list.
.It Cm carpdev Ar iface
Attach to
.Ar iface .
If not specified, the kernel will attempt to select an interface with
a subnet matching that of the carp interface.
.It Cm carppeer Ar peer_address
Send the carp advertisements to a specified
point-to-point peer or multicast group instead of sending the messages
to the default carp multicast group.
The
.Ar peer_address
is the IP address of the other host taking part in the carp cluster.
With this option,
.Xr carp 4
traffic can be protected using
.Xr ipsec 4
and it may be desired in networks that do not allow or have problems
with IPv4 multicast traffic.
.It Fl carppeer
Send the advertisements to the default carp multicast
group.
.It Cm pass Ar passphrase
Set the authentication key to
.Ar passphrase .
There is no passphrase by default.
.It Cm state Ar state
Explicitly force the interface to enter this state.
Valid states are
.Ar init ,
.Ar backup ,
and
.Ar master .
.It Cm vhid Ar n
Set the virtual host ID to
.Ar n .
Acceptable values are 1 to 255.
.El
.Pp
Taken together, the
.Cm advbase
and
.Cm advskew
indicate how frequently, in seconds, the host will advertise the fact that it
considers itself master of the virtual host.
The formula is
.Cm advbase
+
.Pf ( Cm advskew
/ 256).
If the master does not advertise within three times this interval, this host
will begin advertising as master.
.\" IEEE 802.11
.Sh IEEE 802.11 (WIRELESS DEVICES)
.nr nS 1
.Bk -words
.Nm ifconfig
.Ar wireless-interface
.Op Oo Fl Oc Ns Cm bssid Ar bssid
.Op Oo Fl Oc Ns Cm chan Op Ar n
.Op Oo Fl Oc Ns Cm nwflag Ar flag
.Op Oo Fl Oc Ns Cm nwid Ar id
.Op Oo Fl Oc Ns Cm nwkey Ar key
.Op Oo Fl Oc Ns Cm powersave Op Ar duration
.Op Cm scan
.Op Oo Fl Oc Ns Cm txpower Ar dBm
.Op Oo Fl Oc Ns Cm wpa
.Op Cm wpaakms Ar akm,akm,...
.Op Cm wpaciphers Ar cipher,cipher,...
.Op Cm wpagroupcipher Ar cipher
.Op Oo Fl Oc Ns Cm wpakey Ar passphrase | hexkey
.Op Cm wpaprotos Ar proto,proto,...
.Ek
.nr nS 0
.Pp
The following options are available for a wireless interface:
.Bl -tag -width Ds
.It Cm bssid Ar bssid
Set the desired BSSID.
.It Fl bssid
Unset the desired BSSID.
The interface will automatically select a BSSID in this mode, which is
the default.
.It Cm chan Op Ar n
Set the channel (radio frequency) to
.Ar n .
.Pp
With no channel specified,
show the list of channels supported by the device.
.It Fl chan
Unset the desired channel.
It doesn't affect the channel to be created for IBSS or Host AP mode.
.It Cm nwflag Ar flag
Set specified flag.
The flag name can be either
.Ql hidenwid
or
.Ql nobridge .
The
.Ql hidenwid
flag will hide the network ID (ESSID) in beacon frames when operating
in Host AP mode.
It will also prevent responses to probe requests with an unspecified
network ID.
The
.Ql nobridge
flag will disable the direct bridging of frames between associated
nodes when operating in Host AP mode.
Setting this flag will block and filter direct inter-station
communications.
.Pp
Note that the
.Ql hidenwid
and
.Ql nobridge
options do not provide any security.
The hidden network ID will be sent in clear text by associating
stations and can be easily discovered with tools like
.Xr tcpdump 8
and
.Xr hostapd 8 .
.It Fl nwflag Ar flag
Remove specified flag.
.It Cm nwid Ar id
Configure network ID.
The
.Ar id
can either be any text string up to 32 characters in length,
or a series of hexadecimal digits up to 64 digits.
The empty string allows the interface to connect to any available
access points.
Note that network ID is synonymous with Extended Service Set ID (ESSID).
.It Fl nwid
Set the network ID to the empty string to allow the interface to connect
to any available access point.
.It Cm nwkey Ar key
Enable WEP encryption using the specified
.Ar key .
The
.Ar key
can either be a string, a series of hexadecimal digits (preceded by
.So 0x Sc ) ,
or a set of keys
of the form
.Dq n:k1,k2,k3,k4
where
.Sq n
specifies which of the keys will be used for transmitted packets,
and the four keys,
.Dq k1
through
.Dq k4 ,
are configured as WEP keys.
If a set of keys is specified, a comma
.Pq Sq \&,
within the key must be escaped with a backslash.
Note that if multiple keys are used, their order must be the same within
the network.
.Pp
The length of each key must be either 40 bits for 64-bit encryption
(5-character ASCII string
or 10 hexadecimal digits)
or 104 bits for 128-bit encryption
(13-character ASCII string
or 26 hexadecimal digits).
.It Fl nwkey
Disable WEP encryption.
.It Cm nwkey Cm persist
Enable WEP encryption using the persistent key stored in the network card.
.It Cm nwkey Cm persist : Ns Ar key
Write
.Ar key
to the persistent memory of the network card, and
enable WEP encryption using that
.Ar key .
.It Cm powersave Op Ar duration
Enable 802.11 power saving mode.
Optionally set the receiver sleep duration (in milliseconds).
.It Fl powersave
Disable 802.11 power saving mode.
.It Cm scan
Show the results of an access point scan.
In Host AP mode, this will dump the list of known nodes without scanning.
.It Cm txpower Ar dBm
Set the transmit power.
The driver will disable any auto level and transmit power controls in this
mode.
.It Fl txpower
Disable manual transmit power mode and enable any auto level and transmit
power controls.
.It Cm wpa
Enable Wi-Fi Protected Access.
WPA is a Wi-Fi Alliance protocol based on the IEEE 802.11i standard.
It was designed to enhance the security of wireless networks.
Notice that not all drivers support WPA.
Check the driver's manual page to know if this option is supported.
.It Fl wpa
Disable Wi-Fi Protected Access.
.It Cm wpaakms Ar akm,akm,...
Set the comma-separated list of allowed authentication and key management
protocols.
.Pp
The supported values are
.Dq psk
and
.Dq 802.1x .
.Ar psk
authentication (also known as personal mode) uses a 256-bit pre-shared key.
.Ar 802.1x
authentication (also known as enterprise mode) is meant to be used with
an external IEEE 802.1X authentication server,
but is currently unsupported.
The default value is
.Dq psk .
.Dq psk
can only be used if a pre-shared key is configured using the
.Cm wpakey
option.
.It Cm wpaciphers Ar cipher,cipher,...
Set the comma-separated list of allowed pairwise ciphers.
.Pp
The supported values are
.Dq tkip ,
.Dq ccmp ,
and
.Dq usegroup .
.Ar usegroup
specifies that no pairwise ciphers are supported and that only group keys
should be used.
The default value is
.Dq tkip,ccmp .
If multiple pairwise ciphers are specified, the pairwise cipher will
be negotiated between the station and the access point at association
time.
A station will always try to use
.Ar ccmp
over
.Ar tkip
if both ciphers are allowed and supported by the access point.
If the selected cipher is not supported by the hardware, software
encryption will be used.
Check the driver's manual page to know which ciphers are supported in
hardware.
.It Cm wpagroupcipher Ar cipher
Set the group cipher used to encrypt broadcast and multicast traffic.
.Pp
The supported values are
.Dq wep40 ,
.Dq wep104 ,
.Dq tkip ,
and
.Dq ccmp .
The default value is
.Dq tkip .
The use of
.Ar wep40
or
.Ar wep104
as the group cipher is discouraged due to weaknesses in WEP.
The
.Cm wpagroupcipher
option is available in Host AP mode only.
A station will always use the group cipher of the BSS.
.It Cm wpakey Ar passphrase | hexkey
Set the WPA key and enable WPA.
The key can be given using either a passphrase or a full length hex key,
starting with 0x.
If a passphrase is used the
.Cm nwid
option must be set prior to specifying the
.Cm wpakey
option, since
.Nm
will hash the nwid along with the passphrase to create the key.
.It Fl wpakey
Delete the pre-shared WPA key and disable WPA.
.It Cm wpaprotos Ar proto,proto,...
Set the comma-separated list of allowed WPA protocol versions.
.Pp
The supported values are
.Dq wpa1
and
.Dq wpa2 .
.Ar wpa1
is based on draft 3 of the IEEE 802.11i standard whereas
.Ar wpa2
is based on the ratified standard.
The default value is
.Dq wpa1,wpa2 .
If
.Dq wpa1,wpa2
is specified, a station will always use the
.Ar wpa2
protocol when supported by the access point.
.El
.\" INET6
.Sh INET6
.nr nS 1
.Bk -words
.Nm ifconfig
.Ar inet6-interface
.Op Oo Fl Oc Ns Cm anycast
.Op Oo Fl Oc Ns Cm autoconfprivacy
.Op Cm eui64
.Op Cm pltime Ar n
.Op Oo Fl Oc Ns Cm tentative
.Op Cm vltime Ar n
.Ek
.nr nS 0
.Pp
The following options are available for an
.Xr ip6 4
interface:
.Bl -tag -width Ds
.It Cm anycast
Set the IPv6 anycast address bit.
.It Fl anycast
Clear the IPv6 anycast address bit.
.It Cm autoconfprivacy
Enable privacy extensions for stateless IPv6 address autoconfiguration
(RFC 4941) on the interface.
The purpose of these extensions is to prevent tracking of individual
devices which connect to the IPv6 internet from different networks
using stateless autoconfiguration.
The interface identifier often remains constant and provides the lower
64 bits of an autoconfigured IPv6 address, facilitating tracking of
individual devices (and hence, potentially, users of these devices)
over long periods of time (weeks to months to years).
When these extensions are active, random interface identifiers are used
for autoconfigured addresses.
.Pp
Autoconfigured addresses are also made temporary, which means that they
will automatically be replaced regularly.
Temporary addresses are deprecated after 24 hours.
Once a temporary address has been deprecated, a new temporary address
will be configured upon reception of a router advertisement indicating
that the prefix is still valid.
Deprecated addresses will not be used for new connections as long as a
non-deprecated address remains available.
Temporary addresses become invalid after one week, at which time they
will be removed from the interface.
Address lifetime extension through router advertisements is ignored
for temporary addresses.
.It Fl autoconfprivacy
Disable IPv6 autoconf privacy extensions on the interface.
Currently configured addresses will not be removed until they become
invalid.
.It Cm eui64
Fill the interface index
.Pq the lowermost 64th bit of an IPv6 address
automatically.
.It Cm pltime Ar n
Set preferred lifetime for the address.
.It Cm tentative
Set the IPv6 tentative address bit.
.It Fl tentative
Clear the IPv6 tentative address bit.
.It Cm vltime Ar n
Set valid lifetime for the address.
.El
.\" INTERFACE GROUPS
.Sh INTERFACE GROUPS
.Nm ifconfig
.Fl g
.Ar group-name
.Oo
.Oo Fl Oc Ns Cm carpdemote
.Op Ar number
.Oc
.Pp
The following options are available for interface groups:
.Bl -tag -width Ds
.It Fl g Ar group-name
Specify the group.
.It Cm carpdemote Op Ar number
Increase
.Xr carp 4
demote count for given interface group by
.Ar number .
If
.Ar number
is omitted, it is increased by 1.
.It Fl carpdemote Op Ar number
Decrease
.Xr carp 4
demote count for given interface group by
.Ar number .
If
.Ar number
is omitted, it is decreased by 1.
.El
.\" MPE
.Sh MPE
.Nm ifconfig
.Ar mpe-interface
.Op Cm mplslabel Ar mpls-label
.Pp
The following options are available for an
.Xr mpe 4
interface:
.Bl -tag -width Ds
.It Cm mplslabel Ar mpls-label
Set the MPLS label to
.Ar mpls-label .
This value is a 20-bit number which will be used as the MPLS header for
packets entering the MPLS domain.
.El
.\" PFLOW
.Sh PFLOW
.nr nS 1
.Bk -words
.Nm ifconfig
.Ar pflow-interface
.Op Oo Fl Oc Ns Cm flowdst Ar addr : Ns Ar port
.Op Oo Fl Oc Ns Cm flowsrc Ar addr
.Op Cm pflowproto Ar n
.Ek
.nr nS 0
.Pp
The following options are available for a
.Xr pflow 4
interface:
.Bl -tag -width Ds
.It Cm flowdst Ar addr : Ns Ar port
Set the receiver address and the port for
.Xr pflow 4
packets.
Both must be defined to export pflow data.
.Ar addr
is the IP address and
.Ar port
is the port number of the flow collector.
Pflow data will be sent to this address/port.
.It Fl flowdst
Unset the receiver address and stop sending pflow data.
.It Cm flowsrc Ar addr
Set the source IP address for pflow packets.
.Ar addr
is the IP address used as sender of the UDP packets and may be used to
identify the source of the data on the pflow collector.
.It Fl flowsrc
Unset the source address.
.It Cm pflowproto Ar n
Set the protocol version.
The default is version 5.
.El
.\" PFSYNC
.Sh PFSYNC
.nr nS 1
.Bk -words
.Nm ifconfig
.Ar pfsync-interface
.Op Oo Fl Oc Ns Cm defer
.Op Cm maxupd Ar n
.Op Oo Fl Oc Ns Cm syncdev Ar iface
.Op Oo Fl Oc Ns Cm syncpeer Ar peer_address
.Ek
.nr nS 0
.Pp
The following options are available for a
.Xr pfsync 4
interface:
.Bl -tag -width Ds
.It Cm defer
Defer transmission of the first packet in a state until a peer has
acknowledged that the associated state has been inserted.
See
.Xr pfsync 4
for more information.
.It Fl defer
Do not defer the first packet in a state.
This is the default.
.It Cm maxupd Ar n
Indicate the maximum number
of updates for a single state which can be collapsed into one.
This is an 8-bit number; the default value is 128.
.It Cm syncdev Ar iface
Use the specified interface
to send and receive pfsync state synchronisation messages.
.It Fl syncdev
Stop sending pfsync state synchronisation messages over the network.
.It Cm syncpeer Ar peer_address
Make the pfsync link point-to-point rather than using
multicast to broadcast the state synchronisation messages.
The peer_address is the IP address of the other host taking part in
the pfsync cluster.
With this option,
.Xr pfsync 4
traffic can be protected using
.Xr ipsec 4 .
.It Fl syncpeer
Broadcast the packets using multicast.
.El
.\" PPPOE
.Sh PPPOE
.nr nS 1
.Bk -words
.Nm ifconfig
.Ar pppoe-interface
.Op Cm authkey Ar key
.Op Cm authname Ar name
.Op Cm authproto Ar proto
.Op Oo Fl Oc Ns Cm peerflag Ar flag
.Op Cm peerkey Ar key
.Op Cm peername Ar name
.Op Cm peerproto Ar proto
.Op Oo Fl Oc Ns Cm pppoeac Ar access-concentrator
.Op Cm pppoedev Ar parent-interface
.Op Oo Fl Oc Ns Cm pppoesvc Ar service
.Ek
.nr nS 0
.Pp
.Xr pppoe 4
uses the
.Xr sppp 4
"generic" SPPP framework.
Any options not described in the section immediately following
are described in the
.Sx SPPP
section, below.
.Pp
The following options are available for a
.Xr pppoe 4
interface:
.Bl -tag -width Ds
.It Cm pppoeac Ar access-concentrator
Set the name of the access-concentrator.
.It Fl pppoeac
Clear a previously set access-concentrator name.
.It Cm pppoedev Ar parent-interface
Set the name of the interface through which
packets will be transmitted and received.
.It Cm pppoesvc Ar service
Set the service name of the interface.
.It Fl pppoesvc
Clear a previously set service name.
.El
.\" SPPP
.Sh SPPP (PPP LINK CONTROL PROTOCOL)
.nr nS 1
.Bk -words
.Nm
.Ar sppp-interface
.Op Cm authkey Ar key
.Op Cm authname Ar name
.Op Cm authproto Ar proto
.Op Oo Fl Oc Ns Cm peerflag Ar flag
.Op Cm peerkey Ar key
.Op Cm peername Ar name
.Op Cm peerproto Ar proto
.Ek
.nr nS 0
.Pp
The following options are available for an
.Xr sppp 4
or
.Xr pppoe 4
interface:
.Bl -tag -width Ds
.It Cm authkey Ar key
Set the client key or password for the PPP authentication protocol.
.It Cm authname Ar name
Set the client name for the PPP authentication protocol.
.It Cm authproto Ar proto
Set the PPP authentication protocol on the specified
interface acting as a client.
The protocol name can be either
.Ql chap ,
.Ql pap ,
or
.Ql none .
In the latter case, authentication will be turned off.
.It Cm peerflag Ar flag
Set a specified PPP flag for the remote authenticator.
The flag name can be either
.Ql callin
or
.Ql norechallenge .
The
.Ql callin
flag will require the remote peer to authenticate only when he's
calling in, but not when the peer is called by the local client.
This is required for some peers that do not implement the
authentication protocols symmetrically.
The
.Ql norechallenge
flag is only meaningful with the CHAP protocol to not re-challenge
once the initial CHAP handshake has been successful.
This is used to work around broken peer implementations that can't
grok being re-challenged once the connection is up.
.It Fl peerflag Ar flag
Remove a specified PPP flag for the remote authenticator.
.It Cm peerkey Ar key
Set the authenticator key or password for the PPP authentication protocol.
.It Cm peername Ar name
Set the authenticator name for the PPP authentication protocol.
.It Cm peerproto Ar proto
Set the PPP authentication protocol on the specified
interface acting as an authenticator.
The protocol name can be either
.Ql chap ,
.Ql pap ,
or
.Ql none .
In the latter case, authentication will be turned off.
.El
.\" TRUNK
.Sh TRUNK
.Nm ifconfig
.Ar trunk-interface
.Op Oo Fl Oc Ns Cm trunkport Ar child-iface
.Op Cm trunkproto Ar proto
.Pp
The following options are available for a
.Xr trunk 4
interface:
.Bl -tag -width Ds
.It Cm trunkport Ar child-iface
Add
.Ar child-iface
as a trunk port.
.It Fl trunkport Ar child-iface
Remove the trunk port
.Ar child-iface .
.It Cm trunkproto Ar proto
Set the trunk protocol.
Refer to
.Xr trunk 4
for a complete list of the available protocols,
.El
.\" TUNNEL
.Sh TUNNEL
.nr nS 1
.Bk -words
.Nm ifconfig
.Ar tunnel-interface
.Op Cm deletetunnel Ar src_address dest_address
.Op Oo Fl Oc Ns Cm keepalive Ar period count
.Op Cm tunnel Ar src_address dest_address
.Op Cm tunneldomain Ar route-id
.Ek
.nr nS 0
.Pp
The following options are available for a tunnel interface:
.Bl -tag -width Ds
.It Cm deletetunnel Ar src_address dest_address
Remove the source and destination tunnel addresses.
.It Cm keepalive Ar period count
Enable
.Xr gre 4
keepalive with a packet sent every
.Ar period
seconds.
A second timer is run with a timeout of
.Ar count
*
.Ar period .
If no keepalive response is received during that time, the link is considered
down.
The minimal usable
.Ar count
is 2 since the round-trip time of keepalive packets needs to be accounted for.
.It Fl keepalive
Disable the
.Xr gre 4
keepalive mechanism.
.It Cm tunnel Ar src_address dest_address
Set the source and destination tunnel addresses on a tunnel interface,
including
.Xr gif 4 .
Packets routed to this interface will be encapsulated in
IPv4 or IPv6, depending on the source and destination address families.
Both addresses must be of the same family.
.It Cm tunneldomain Ar route-id
Use routing table
.Ar route-id
instead of the default table.
The tunnel does not need to terminate in the same routing domain as the
interface itself.
.Ar route-id
can be set to any valid routing table ID;
the corresponding routing domain is derived from this table.
.El
.\" VLAN
.Sh VLAN
.nr nS 1
.Bk -words
.Nm ifconfig
.Ar vlan-interface
.Op Cm vlan Ar vlan-tag
.Op Oo Fl Oc Ns Cm vlandev Ar parent-interface
.Ek
.nr nS 0
.Pp
The following options are available for a
.Xr vlan 4
interface:
.Bl -tag -width Ds
.It Cm vlan Ar vlan-tag
Set the vlan tag value
to
.Ar vlan-tag .
This value is a 12-bit number which is used to create an 802.1Q
vlan header for packets sent from the vlan interface.
This value cannot be changed once it is set for an interface.
.It Cm vlandev Ar parent-interface
Associate with interface
.Ar parent-interface .
Packets transmitted through the vlan interface will be
diverted to the specified interface
.Ar parent-interface
with 802.1Q vlan encapsulation.
Packets with 802.1Q encapsulation received
by the parent interface with the correct vlan tag will be diverted to
the associated vlan pseudo-device.
The vlan interface is assigned a
copy of the parent interface's flags and the parent's Ethernet address.
If
.Cm vlandev
and
.Cm vlan
are not set at the same time, the vlan tag will be inferred from
the interface name, for instance
.Cm vlan5
will be assigned 802.1Q tag 5.
.It Fl vlandev
Disassociate from the parent interface.
This breaks the link between the vlan interface and its parent,
clears its vlan tag, flags, and link address, and shuts the interface down.
.El
.Sh EXAMPLES
Assign the
address of 192.168.1.10 with a network mask of
255.255.255.0 to interface fxp0:
.Pp
.Dl # ifconfig fxp0 inet 192.168.1.10 netmask 255.255.255.0
.Pp
Configure the xl0 interface to use 100baseTX, full duplex:
.Pp
.Dl # ifconfig xl0 media 100baseTX mediaopt full-duplex
.Pp
Label the em0 interface as an uplink:
.Pp
.Dl # ifconfig em0 description \&"Uplink to Gigabit Switch 2\&"
.Pp
Create the gif1 network interface:
.Pp
.Dl # ifconfig gif1 create
.Pp
Scan for wireless networks using bwi0:
.Pp
.Dl # ifconfig bwi0 scan
.Sh DIAGNOSTICS
Messages indicating the specified interface does not exist, the
requested address is unknown, or the user is not privileged and
tried to alter an interface's configuration.
.Sh SEE ALSO
.Xr netstat 1 ,
.Xr ifmedia 4 ,
.Xr inet 4 ,
.Xr intro 4 ,
.Xr netintro 4 ,
.Xr hostname.if 5 ,
.Xr hosts 5 ,
.Xr networks 5 ,
.Xr rc 8 ,
.Xr tcpdump 8
.Sh HISTORY
The
.Nm
command appeared in
.Bx 4.2 .