IFCONFIG(8)

NAME
ifconfig - configure network interface parameters

SYNOPSIS
ifconfig [-AaC] [interface] [address_family] [ address [dest_address]] [parameters]

DESCRIPTION
The ifconfig utility is used to assign an address to a network interface and/or configure network interface parameters. Generally speaking, hostname.if(5) files are used at boot-time to define the network address of each interface present on a machine; ifconfig is used at a later time to redefine an interface's address or other operating parameters.

ifconfig displays the current configuration for a network interface when no optional parameters are supplied. If a protocol family is specified, ifconfig will report only the details specific to that protocol family. If no parameters are provided, a summary of all interfaces is provided.

Only the superuser may modify the configuration of a network interface.

The following options are available:

-A  Causes full interface alias information for each interface to be displayed.

-a  Causes ifconfig to print information on all interfaces. The protocol family may be specified as well. This is the default, if no parameters are given to ifconfig.

-C  Print the names of all network pseudo-devices that can be created dynamically at runtime using ifconfig create.

interface
    The interface parameter is a string of the form “name unit”, for example, “en0”. If no optional parameters are supplied, this string can instead be just “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, “fxp” will display all fxp(4) interfaces).

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 “inet” and “inet6”.

address
    Internet version 4 and 6 addresses take the form of a host name present in the host name database, hosts(5); “dot” notation (IPv4); colon separated (IPv6); or CIDR notation.

dest_address
    Specify the address of the correspondent on the other end of a point-to-point link.

The following parameters may be set with ifconfig:

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.

-alias
    A synonym for delete. Use of this option is discouraged in favour of delete.

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.

-arp
    Disable the use of ARP.

autoconf
    Enable autoconfiguration. Valid for “inet6” only. If autoconf is enabled router advertisements are accepted on this interface and the kernel sends periodic router solicitations from this interface.

-autoconf
    Disable autoconfiguration.

broadcast 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.

create
    Create the specified network pseudo-device. At least the following devices can be created on demand:

    bridge(4), carp(4), enc(4), gif(4), gre(4), lo(4), mpe(4), mpw(4), pflog(4), pflow(4), pfsync(4), ppp(4), pppoe(4), trunk(4), tun(4), vether(4), vlan(4)

debug
    Enable driver-dependent debugging code; usually, this turns on extra console error logging.

-debug
    Disable driver-dependent debugging code.

delete
    Remove the default inet address associated with the interface, including any netmask or destination address configured with it. An address and address family can be given to make the deletion more specific.

description value
    Specify a description of the interface. This can be used to label interfaces in situations where they may otherwise be difficult to distinguish.

-description
    Clear the interface description.

destroy
    Destroy the specified network pseudo-device.

down
    Mark an interface “down”. When an interface is marked “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.

group group-name
    Assign the interface to a “group”. group-name may not be longer than 15 characters and must not end with a digit. Any interface can be in multiple groups.

    For instance, a group could be used to create a hardware independent pf(4) ruleset (i.e. not one based on the names of NICs) using existing (egress, carp, etc.) or user-defined groups.

    Some interfaces belong to specific groups by default:

    -   All interfaces are members of the all interface group.
    -   Cloned interfaces are members of their interface family group. For example, a PPP interface such as ppp0 is a member of the ppp interface family group.
    -   pppx(4) interfaces are members of the pppx interface group.
    -   The interface(s) the default route(s) point to are members of the egress interface group.
    -   IEEE 802.11 wireless interfaces are members of the wlan interface group.
    -   Any interfaces used for network booting are members of the netboot interface group.

-group group-name
    Remove the interface from the given “group”.

hwfeatures
    Display the interface hardware features:

    CSUM_IPv4
        The device supports IPv4 checksum offload.
    CSUM_TCPv4
        As above, for TCP in IPv4 datagrams.
    CSUM_UDPv4
        As above, for UDP.
    VLAN_MTU
        The device can handle full sized frames, plus the size of the vlan(4) tag.
    VLAN_HWTAGGING
        On transmit, the device can add the vlan(4) tag.
    CSUM_TCPv6
        As CSUM_TCPv4, but supports IPv6 datagrams.
    CSUM_UDPv6
        As above, for UDP.
    WOL The device supports Wake on LAN (WoL).
    hardmtu
        The maximum MTU supported.

-inet
    Remove all configured inet(4) addresses on the given interface.

-inet6
    Disable inet6(4) on the given interface and remove all configured inet6(4) addresses, including the link-local ones. This is the default. To turn inet6 on, use eui64, use autoconf or assign any inet6 address.

instance minst
    Set the media instance to 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.

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 select the connector type for some Ethernet cards. Refer to the man page for the specific driver for more information.

-link[0-2]
    Disable special processing at the link level with the specified interface.

lladdr etheraddr|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.

media [type]
    Set the media type of the interface to type. If no argument is given, display a list of all available media.

    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 “10base5” or “AUI” would change the currently active connector to the AUI port. Setting it to “10baseT” or “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:

        $ ifconfig interface media

mediaopt opts
    Set the specified media options on the interface. 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:

        $ ifconfig interface media

-mediaopt opts
    Disable the specified media options on the interface.

metric nhops
    Set the routing metric of the interface to nhops, default 0. The routing metric can be used by routing protocols. Higher metrics have the effect of making a route less favorable.

mode mode
    If the driver for the interface supports the media selection system, set the specified operating mode on the interface to the given mode. For IEEE 802.11 wireless interfaces that support multiple operating modes, this directive is used to select between 802.11a (“11a”), 802.11b (“11b”), and 802.11g (“11g”) operating modes.

mpls
    Enable Multiprotocol Label Switching (MPLS) on the interface, allowing it to send and receive MPLS traffic.

-mpls
    Disable MPLS on the interface.

mtu value
    Set the MTU for this device to the given value. Cloned routes inherit this value as a default. For Ethernet devices which support setting the MTU, a value greater than 1500 enables jumbo frames. The hardmtu output from hwfeatures shows the maximum supported MTU.

netmask 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 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.

prefixlen n
    (inet and inet6 only) Effect is similar to netmask, but you can specify prefix length by digits.

priority n
    Set the interface routing priority to n. This will influence the default routing priority of new static routes added to the kernel. n is in the range of 0 to 15 with smaller numbers being better.

rdomain rdomainid
    Attach the interface to the routing domain with the specified rdomainid. Interfaces in different routing domains are separated and can not directly pass traffic between each other. It is therefore possible to reuse the same addresses in different routing domains. If the specified rdomain does not yet exist it will be created, including a routing table with the same id. By default all interfaces belong to routing domain 0.

rtlabel route-label
    (inet) Attach route-label to new network routes of the specified interface. Route labels can be used to implement policy routing; see route(4), route(8), and pf.conf(5).

-rtlabel
    Clear the route label.

timeslot timeslot_range
    Set the timeslot range map, which is used to control which channels an interface device uses.

up  Mark an interface “up”. This may be used to enable an interface after an 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.

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 arp(8).

-wol
    Disable WoL. WoL is disabled at boot by the driver, if possible.

ifconfig supports a multitude of sub-types, described in the following sections:

-   bridge(4)
-   carp(4)
-   IEEE 802.11 (wireless devices)
-   inet6(4)
-   interface groups
-   mpe(4)
-   mpw(4)
-   pflow(4)
-   pfsync(4)
-   pppoe(4)
-   sppp(4) (PPP Link Control Protocol)
-   trunk(4)
-   tunnel (gif(4) and gre(4))
-   vlan(4)

BRIDGE
The following options are available for a bridge(4) interface:

add interface
    Add 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.

addr
    Display the addresses that have been learned by the bridge.

addspan interface
    Add interface as a span port on the bridge.

autoedge interface
    Automatically detect the spanning tree edge port status on interface. This is the default for interfaces added to the bridge.

-autoedge interface
    Disable automatic spanning tree edge port detection on interface.

autoptp interface
    Automatically detect the point-to-point status on interface by checking the full duplex link status. This is the default for interfaces added to the bridge.

-autoptp interface
    Disable automatic point-to-point link detection on interface.

blocknonip interface
    Mark 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.

-blocknonip interface
    Allow non-IPv4, IPv6, ARP, or Reverse ARP packets through interface.

del interface
    Remove interface from the bridge. Promiscuous mode is turned off for the interface when it is removed from the bridge.

deladdr address
    Delete address from the cache.

delspan interface
    Delete interface from the list of span ports of the bridge.

discover interface
    Mark 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.

-discover interface
    Mark 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.

down
    Stop the bridge from forwarding packets.

edge interface
    Set 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.

-edge interface
    Disable edge port status on interface.

flush
    Remove all dynamically learned addresses from the cache.

flushall
    Remove all addresses from the cache including static addresses.

flushrule interface
    Remove all Ethernet MAC filtering rules from interface.

fwddelay time
    Set the time (in seconds) before an interface begins forwarding packets. Defaults to 15 seconds, minimum of 4, maximum of 30.

hellotime 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 proto command for setting the protocol version.

holdcnt 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.

ifcost interface num
    Set the spanning tree path cost of interface to num. Defaults to 55, minimum of 1, maximum of 200000000 in RSTP mode, and maximum of 65535 in STP mode.

-ifcost interface
    Automatically calculate the spanning tree priority of interface based on the current link speed, interface status, and spanning tree mode. This is the default for interfaces added to the bridge.

ifpriority interface num
    Set the spanning tree priority of interface to num. Defaults to 128, minimum of 0, maximum of 240.

learn interface
    Mark 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.

-learn interface
    Mark interface so that the source address of packets received from interface are not entered into the address cache.

link0
    Setting this flag stops all IP multicast packets from being forwarded by the bridge.

-link0
    Clear the link0 flag on the bridge interface.

link1
    Setting this flag stops all non-IP multicast packets from being forwarded by the bridge.

-link1
    Clear the link1 flag on the bridge interface.

link2
    Setting this flag causes all packets to be passed on to ipsec(4) for processing, based on the policies established by the administrator using the ipsecctl(8) command and 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 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)).

-link2
    Clear the link2 flag on the bridge interface.

maxaddr size
    Set the address cache size to size. The default is 100 entries.

maxage time
    Set the time (in seconds) that a spanning tree protocol configuration is valid. Defaults to 20 seconds, minimum of 6, maximum of 40.

proto value
    Force the spanning tree protocol version. The available values are rstp to operate in the default Rapid Spanning Tree (RSTP) mode or stp to force operation in Spanning Tree (STP) mode with rapid transitions disabled.

ptp interface
    Set 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 trunk(4) with at least two physical links to the same network segment.

-ptp interface
    Disable point-to-point link status on 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.

    rule block|pass [in | out] on interface [src address] [dst address] [tag tagname] Add a filtering rule to an interface. Rules have a similar syntax to those in pf.conf(5). Rules can be used to selectively block or pass frames based on Ethernet MAC addresses. They can also tag packets for 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).

rulefile filename
    Load a set of rules from the file filename.

rules interface
    Display the active filtering rules in use on interface.

spanpriority num
    Set the spanning priority of this bridge to num. Defaults to 32768, minimum of 0, maximum of 61440.

static interface address
    Add a static entry into the address cache pointing to interface. Static entries are never aged out of the cache or replaced, even if the address is seen on a different interface.

stp interface
    Enable spanning tree protocol on interface.

-stp interface
    Disable spanning tree protocol on interface. This is the default for interfaces added to the bridge.

timeout time
    Set the timeout, in seconds, for addresses in the cache to time. The default is 240 seconds. If time is set to zero, then entries will not be expired.

up  Start the bridge forwarding packets.

CARP
ifconfig carp-interface [advbase n] [advskew n] [balancing mode] [carpnodes vhid:advskew,vhid:advskew,...] [carpdev iface] [[-]carppeer peer_address] [pass passphrase] [state state] [vhid host-id]

The following options are available for a carp(4) interface:

advbase n
    Set the base advertisement interval to n seconds. Acceptable values are 0 to 254; the default value is 1 second.

advskew n
    Skew the advertisement interval by n. Acceptable values are 0 to 254; the default value is 0.

balancing mode
    Set the load balancing mode to mode. Valid modes are arp, ip, ip-stealth, and ip-unicast.

carpnodes vhid:advskew,vhid:advskew,...
    Create a load balancing group consisting of up to 32 nodes. Each node is specified as a vhid:advskew tuple in a comma separated list.

carpdev iface
    Attach to parent interface iface.

carppeer 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 peer_address is the IP address of the other host taking part in the carp cluster. With this option, carp(4) traffic can be protected using ipsec(4) and it may be desired in networks that do not allow or have problems with IPv4 multicast traffic.

-carppeer
    Send the advertisements to the default carp multicast group.

pass passphrase
    Set the authentication key to passphrase. There is no passphrase by default.

state state
    Explicitly force the interface to enter this state. Valid states are init, backup, and master.

vhid n
    Set the virtual host ID to n. Acceptable values are 1 to 255.

Taken together, the advbase and advskew indicate how frequently, in seconds, the host will advertise the fact that it considers itself master of the virtual host. The formula is advbase + (advskew / 256). If the master does not advertise within three times this interval, this host will begin advertising as master.

IEEE 802.11 (WIRELESS DEVICES)
ifconfig wireless-interface [[-]bssid bssid] [[-]chan [n]] [[-]nwflag flag] [[-]nwid id] [[-]nwkey key] [[-]powersave [duration]] [scan] [[-]txpower dBm] [[-]wpa] [wpaakms akm,akm,...] [wpaciphers cipher,cipher,...] [wpagroupcipher cipher] [[-]wpakey passphrase | hexkey] [wpaprotos proto,proto,...]

The following options are available for a wireless interface:

bssid bssid
    Set the desired BSSID.

-bssid
    Unset the desired BSSID. The interface will automatically select a BSSID in this mode, which is the default.

chan [n]
    Set the channel (radio frequency) to n.

    With no channel specified, show the list of channels supported by the device.

-chan
    Unset the desired channel. It doesn't affect the channel to be created for IBSS or Host AP mode.

nwflag flag
    Set specified flag. The flag name can be either ‘hidenwid’ or ‘nobridge’. The ‘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 ‘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.

    Note that the ‘hidenwid’ and ‘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 tcpdump(8) and hostapd(8).

-nwflag flag
    Remove specified flag.

nwid id
    Configure network ID. The 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).

-nwid
    Set the network ID to the empty string to allow the interface to connect to any available access point.

nwkey key
    Enable WEP encryption using the specified key. The key can either be a string, a series of hexadecimal digits (preceded by ‘0x’), or a set of keys of the form “n:k1,k2,k3,k4” where ‘n’ specifies which of the keys will be used for transmitted packets, and the four keys, “k1” through “k4”, are configured as WEP keys. If a set of keys is specified, a comma (‘’), 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.

    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).

-nwkey
    Disable WEP encryption.

nwkey persist
    Enable WEP encryption using the persistent key stored in the network card.

nwkey persist:key
    Write key to the persistent memory of the network card, and enable WEP encryption using that key.

powersave [duration]
    Enable 802.11 power saving mode. Optionally set the receiver sleep duration (in milliseconds).

-powersave
    Disable 802.11 power saving mode.

scan
    Show the results of an access point scan. In Host AP mode, this will dump the list of known nodes without scanning.

txpower dBm
    Set the transmit power. The driver will disable any auto level and transmit power controls in this mode.

-txpower
    Disable manual transmit power mode and enable any auto level and transmit power controls.

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.

-wpa
    Disable Wi-Fi Protected Access.

wpaakms akm,akm,...
    Set the comma-separated list of allowed authentication and key management protocols.

    The supported values are “psk” and “802.1x”. psk authentication (also known as personal mode) uses a 256-bit pre-shared key. 802.1x authentication (also known as enterprise mode) is used with an external IEEE 802.1X authentication server, such as wpa_supplicant. The default value is “psk”. “psk” can only be used if a pre-shared key is configured using the wpakey option.

wpaciphers cipher,cipher,...
    Set the comma-separated list of allowed pairwise ciphers.

    The supported values are “tkip”, “ccmp”, and “usegroup”. usegroup specifies that no pairwise ciphers are supported and that only group keys should be used. The default value is “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 ccmp over 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.

wpagroupcipher cipher
    Set the group cipher used to encrypt broadcast and multicast traffic.

    The supported values are “wep40”, “wep104”, “tkip”, and “ccmp”. The default value is “tkip”. The use of wep40 or wep104 as the group cipher is discouraged due to weaknesses in WEP. The wpagroupcipher option is available in Host AP mode only. A station will always use the group cipher of the BSS.

wpakey 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 nwid option must be set prior to specifying the wpakey option, since ifconfig will hash the nwid along with the passphrase to create the key.

-wpakey
    Delete the pre-shared WPA key and disable WPA.

wpaprotos proto,proto,...
    Set the comma-separated list of allowed WPA protocol versions.

    The supported values are “wpa1” and “wpa2”. wpa1 is based on draft 3 of the IEEE 802.11i standard whereas wpa2 is based on the ratified standard. The default value is “wpa1,wpa2”. If “wpa1,wpa2” is specified, a station will always use the wpa2 protocol when supported by the access point.

INET6
ifconfig inet6-interface [[-]anycast] [[-]autoconfprivacy] [eui64] [pltime n] [[-]tentative] [vltime n]

The following options are available for an ip6(4) interface:

anycast
    Set the IPv6 anycast address bit.

-anycast
    Clear the IPv6 anycast address bit.

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.

    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.

-autoconfprivacy
    Disable IPv6 autoconf privacy extensions on the interface. Currently configured addresses will not be removed until they become invalid.

eui64
    Fill the interface index (the lowermost 64th bit of an IPv6 address) automatically.

pltime n
    Set preferred lifetime for the address.

tentative
    Set the IPv6 tentative address bit.

-tentative
    Clear the IPv6 tentative address bit.

vltime n
    Set valid lifetime for the address.

INTERFACE GROUPS
ifconfig -g group-name [ [-]carpdemote [number]]

The following options are available for interface groups:

-g group-name
    Specify the group.

carpdemote [number]
    Increase carp(4) demote count for given interface group by number. Acceptable values are 0 to 128. If number is omitted, it is increased by 1. Demote count can be set up to 255.

-carpdemote [number]
    Decrease carp(4) demote count for given interface group by number. Acceptable values are 0 to 128. If number is omitted, it is decreased by 1.

MPE
ifconfig mpe-interface [mplslabel mpls-label]

The following options are available for an mpe(4) interface:

mplslabel mpls-label
    Set the MPLS label to mpls-label. This value is a 20-bit number which will be used as the MPLS header for packets entering the MPLS domain.

MPW
ifconfig mpw-interface [[-]controlword] [encap encapsulation] [mpwlabel local-label remote-label neighbor dest-address]

The following options are available for an mpw(4) interface:

controlword
    Configure the mpw interface to use control-word.

-controlword
    Remove control-word configuration from the interface.

encap encapsulation
    Configures the mpw encapsulation type with value encapsulation which can be ethernet or ethernet-tagged. By default it's assumed to be ethernet mode.

mpwlabel local-label remote-label
    Set mpw local label to local-label and remote label to remote-label. The local-label is a 20-bit number which will be used to create a local label route to the mpw interface and the remote-label is another 20-bit number which will be used to create the output label header.

neighbor dest-address
    Sets the destination address where this mpw should output. The dest-address is an IPv4 address that will be used to find the nexthop in the MPLS network.

PFLOW
ifconfig pflow-interface [[-]flowdst addr:port] [[-]flowsrc addr] [pflowproto n]

The following options are available for a pflow(4) interface:

flowdst addr:port
    Set the receiver address and the port for pflow(4) packets. Both must be defined to export pflow data. addr is the IP address and port is the port number of the flow collector. Pflow data will be sent to this address/port.

-flowdst
    Unset the receiver address and stop sending pflow data.

flowsrc addr
    Set the source IP address for pflow packets. 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.

-flowsrc
    Unset the source address.

pflowproto n
    Set the protocol version. The default is version 5.

PFSYNC
ifconfig pfsync-interface [[-]defer] [maxupd n] [[-]syncdev iface] [[-]syncpeer peer_address]

The following options are available for a pfsync(4) interface:

defer
    Defer transmission of the first packet in a state until a peer has acknowledged that the associated state has been inserted. See pfsync(4) for more information.

-defer
    Do not defer the first packet in a state. This is the default.

maxupd 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.

syncdev iface
    Use the specified interface to send and receive pfsync state synchronisation messages.

-syncdev
    Stop sending pfsync state synchronisation messages over the network.

syncpeer 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, pfsync(4) traffic can be protected using ipsec(4).

-syncpeer
    Broadcast the packets using multicast.

PPPOE
ifconfig pppoe-interface [authkey key] [authname name] [authproto proto] [[-]peerflag flag] [peerkey key] [peername name] [peerproto proto] [[-]pppoeac access-concentrator] [pppoedev parent-interface] [[-]pppoesvc service]

pppoe(4) uses the sppp(4) "generic" SPPP framework. Any options not described in the section immediately following are described in the SPPP section, below.

The following options are available for a pppoe(4) interface:

pppoeac access-concentrator
    Set the name of the access-concentrator.

-pppoeac
    Clear a previously set access-concentrator name.

pppoedev parent-interface
    Set the name of the interface through which packets will be transmitted and received.

pppoesvc service
    Set the service name of the interface.

-pppoesvc
    Clear a previously set service name.

SPPP (PPP LINK CONTROL PROTOCOL)
ifconfig sppp-interface [authkey key] [authname name] [authproto proto] [[-]peerflag flag] [peerkey key] [peername name] [peerproto proto]

The following options are available for an sppp(4) or pppoe(4) interface:

authkey key
    Set the client key or password for the PPP authentication protocol.

authname name
    Set the client name for the PPP authentication protocol.

authproto proto
    Set the PPP authentication protocol on the specified interface acting as a client. The protocol name can be either ‘chap’, ‘pap’, or ‘none’. In the latter case, authentication will be turned off.

peerflag flag
    Set a specified PPP flag for the remote authenticator. The flag name can be either ‘callin’ or ‘norechallenge’. The ‘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 ‘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.

-peerflag flag
    Remove a specified PPP flag for the remote authenticator.

peerkey key
    Set the authenticator key or password for the PPP authentication protocol.

peername name
    Set the authenticator name for the PPP authentication protocol.

peerproto proto
    Set the PPP authentication protocol on the specified interface acting as an authenticator. The protocol name can be either ‘chap’, ‘pap’, or ‘none’. In the latter case, authentication will be turned off.

TRUNK
ifconfig trunk-interface [[-]trunkport child-iface] [trunkproto proto]

The following options are available for a trunk(4) interface:

trunkport child-iface
    Add child-iface as a trunk port.

-trunkport child-iface
    Remove the trunk port child-iface.

trunkproto proto
    Set the trunk protocol. Refer to trunk(4) for a complete list of the available protocols,

TUNNEL
ifconfig tunnel-interface [deletetunnel src_address dest_address] [[-]keepalive period count] [tunnel src_address dest_address] [tunneldomain tableid] [vnetid network-id]

The following options are available for a tunnel interface:

deletetunnel src_address dest_address
    Remove the source and destination tunnel addresses.

keepalive period count
    Enable gre(4) keepalive with a packet sent every period seconds. A second timer is run with a timeout of count * period. If no keepalive response is received during that time, the link is considered down. The minimal usable count is 2 since the round-trip time of keepalive packets needs to be accounted for.

-keepalive
    Disable the gre(4) keepalive mechanism.

tunnel src_address dest_address[:dest_port]
    Set the source and destination tunnel addresses on a tunnel interface, including 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. The optional destination port can be specified for interfaces such as vxlan(4), which further encapsulate the packets in UDP datagrams.

tunneldomain tableid
    Use routing table tableid instead of the default table. The tunnel does not need to terminate in the same routing domain as the interface itself. tableid can be set to any valid routing table ID; the corresponding routing domain is derived from this table.

tunnelttl ttl
    Set the IP or multicast TTL of the tunnel packets.

vnetid network-id
    Set the virtual network identifier. This is a number which is used by tunnel protocols such as vxlan(4) to identify packets with a virtual network. The accepted size of the number depends on the individual tunnel protocol; it is a 24-bit number for vxlan(4).

VLAN
ifconfig vlan-interface [vlan vlan-tag] [[-]vlandev parent-interface]

The following options are available for a vlan(4) interface:

vlan vlan-tag
    Set the vlan tag value to 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.

vlandev parent-interface
    Associate with interface parent-interface. Packets transmitted through the vlan interface will be diverted to the specified interface parent-interface with 802.1Q vlan tagging. Packets with 802.1Q tagging 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 vlandev and vlan are not set at the same time, the vlan tag will be inferred from the interface name, for instance vlan5 will be assigned 802.1Q tag 5.

-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.

EXAMPLES
Assign the address of 192.168.1.10 with a network mask of 255.255.255.0 to interface fxp0:

    # ifconfig fxp0 inet 192.168.1.10 netmask 255.255.255.0

Configure the xl0 interface to use 100baseTX, full duplex:

    # ifconfig xl0 media 100baseTX mediaopt full-duplex

Label the em0 interface as an uplink:

    # ifconfig em0 description "Uplink to Gigabit Switch 2"

Create the gif1 network interface:

    # ifconfig gif1 create

Put the athn0 wireless interface into monitor mode:

    # ifconfig athn0 mediaopt monitor

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.

SEE ALSO
netstat(1), ifmedia(4), inet(4), intro(4), netintro(4), hostname.if(5), hosts(5), networks(5), rc(8), tcpdump(8)

HISTORY
The ifconfig command appeared in 4.2BSD.