IFCONFIG(8) BSD System Manager's Manual IFCONFIG(8)
ifconfig - configure network interface parameters
ifconfig interface [address_family] [address [dest_address]] [parameters] ifconfig -A | -Am | -a | -am [address_family] ifconfig -C ifconfig -l ifconfig -m interface [address_family] ifconfig interface create ifconfig interface destroy ifconfig carp-interface vhid host-id ifconfig pfsync-interface syncif iface ifconfig pppoe-interface [pppoedev parent-interface] [pppoesvc service] [pppoeac access-concentrator] ifconfig tunnel-interface tunnel src_address dest_address ifconfig tunnel-interface deletetunnel ifconfig vlan-interface vlan vlan-tag vlandev parent-interface
The ifconfig utility is used to assign an address to a network interface and/or configure network interface parameters. ifconfig must be used at boot-time to define the network address of each interface present on a machine; it may also be used at a later time to redefine an interface's address or other operating parameters. To configure a bridge interface, use the brconfig(8) program instead. 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. Only the superuser may modify the configuration of a network interface. The options are as follows: -A Causes full interface alias information for each interface to be displayed. -Am The same as the -A option, but additionally prints interface media information for all interfaces. -a Causes ifconfig to print information on all interfaces. The pro- tocol family may be specified as well. -am The same as the -a option, but additionally prints interface media information for all interfaces. -C Print the names of all network pseudo-devices that can be created dynamically at runtime using ifconfig create. -l Print the names of all network interfaces, except some virtual interfaces like pflog, pfsync, enc, irip, separated by spaces. -m interface Print media information for a given interface. address For the DARPA Internet family, the address is either a host name present in the host name database, hosts(5), or a DARPA Internet address expressed in the Internet standard "dot notation". Internet version 6 addresses are either a host name present in the host name database, hosts(5), or an Internet version 6 ad- dress in standard colon separated form, as described in the inet(3) manual page. For the Xerox Network Systems(tm) and Internetwork Packet Ex- change families, addresses are of the form "net:a.b.c.d.e.f", where "net" is the assigned network number (in decimal), and each of the six bytes of the host number, "a" through "f", are speci- fied in hexadecimal. The host number may be omitted on Ethernet interfaces, which use the hardware physical address, and on in- terfaces other than the first. AppleTalk (LLAP) addresses are specified as "nn.na" ("Network Number.Node Address"). Node ad- dresses are divided into two classes: User Node IDs and Server Node IDs. 1-127($01-$7F) are for User Node IDs while 128- 254($80-$FE) are used for Server Node IDs. Node 0($00) is not al- lowed (unknown) while Node 255($FF) is reserved for the AppleTalk broadcast hardware address (broadcast ID). IPX addresses are specified as listed in the ipx(3) manual page. address_family Specifies the address family which affects interpretation of the remaining parameters. Since an interface can receive transmis- sions in differing protocols with different naming schemes, specifying the address family is recommended. The address or pro- tocol families currently supported are "inet", "inet6", "atalk" and "ipx". 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". In this case, all interfaces of that type will be displayed. For example, "carp" will display the current configuration of all carp(4) interfaces. The following parameters may be set with ifconfig: 802.2 802.2tr 802.3 snap EtherII Set the ipx(3) frame type to be either 802.2, 802.2tr, 802.3, snap, or Ethernet II. advbase n If the driver is a carp(4) pseudo-device, set the base advertisement interval to n seconds. This is an 8-bit number; the default value is 1 second. advskew n If the driver is a carp(4) pseudo-device, skew the adver- tisement interval by n. This is an 8-bit number; the de- fault value is 0. Taken together the advbase and advskew indicate how fre- quently, in seconds, the host will advertise the fact that it considers itself master of the virtual host. The formula is advbase + (advskew / 255 ). If the master does not advertise within three times this interval, this host will begin advertising as master. alias Establish an additional network address for this inter- face. This is sometimes useful when changing network numbers, and one wishes to accept packets addressed to the old interface. -alias Remove the specified network address alias. anycast (inet6 only) Set the IPv6 anycast address bit. -anycast (inet6 only) Clear the IPv6 anycast address bit. arp Enable the use of the Address Resolution Protocol (``ARP''; see arp(4)) 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. 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), gif(4), gre(4), lo(4), ppp(4), pppoe(4), sl(4), tun(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 network address specified. This would be used if you incorrectly specified an alias, or it was no longer needed. deletetunnel Removes the source and destination tunnel addresses, con- figured onto a tunnel interface. dest_address Specify the address of the correspondent on the other end of a point-to-point link. 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 au- tomatically disables routes using the interface. eui64 (inet6 only) Fill the interface index (the lowermost 64th bit of an IPv6 address) automatically. instance minst Set the media instance to minst. This is useful for dev- ices 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 inter- face. These three options are interface specific in actu- al effect; however, they are in general used to select special modes of operation. An example of this is to en- able SLIP compression, or 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. maxupd n If the driver is a pfsync(4) pseudo-device, 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. media type Set the media type of the interface to type. Some inter- faces 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 ei- ther AUI or twisted pair connectors. Setting the media type to "10base5" or "AUI" would change the currently ac- tive 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 $ ifconfig -m interface for a listing of choices. mediaopt opts Set the specified media options on the interface. opts is a comma delimited list of options to apply to the inter- face. Refer to the interface's driver-specific man page for a complete list of available options, or use $ ifconfig -m interface for a listing of choices. -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 is used by the routing protocol (see routed(8)). Higher metrics have the effect of making a route less favorable; metrics are counted as addition hops to the destination network or host. mtu value Set the MTU for this device to the given value. Cloned routes will inherit this value as a default. Currently, not all devices support setting the MTU. netmask mask (inet, inet6) Specify how much of the address to reserve for subdividing networks into subnetworks. The mask in- cludes the network part of the local address and the sub- net part, which is taken from the host field of the ad- dress. 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 net- work 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. nwkey key (IEEE 802.11 devices only) Enable WEP encryption for IEEE 802.11-based wireless network interfaces using the speci- fied 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 multi- ple keys are used, their order must be the same within the network. For IEEE 802.11 wireless networks, the length of each key is restricted to 40 bits, i.e. a 5- character string or 10 hexadecimal digits. WaveLAN/IEEE Gold and newer Prism cards will also accept a 104-bit (13-character) key. -nwkey (IEEE 802.11 devices only) Disable WEP encryption for IEEE 802.11-based wireless network interfaces. nwkey persist (IEEE 802.11 devices only) Enable WEP encryption for IEEE 802.11-based wireless network interfaces with the per- sistent key stored in the network card. nwkey persist:key (IEEE 802.11 devices only) Write key to the persistent memory of the network card, and enable WEP encryption for IEEE 802.11-based wireless network interfaces using that key. pass passphrase If the driver is a carp(4) pseudo-device, set the authen- tication key to passphrase. There is no passphrase by de- fault. phase n The argument n specifies the version (phase) of the Ap- pleTalk network attached to the interface. Values of 1 or 2 are permitted. pltime n (inet6 only) Set preferred lifetime for the address. powersave (IEEE 802.11 devices only) Enable 802.11 power saving mode. -powersave (IEEE 802.11 devices only) Disable 802.11 power saving mode. powersavesleep duration (IEEE 802.11 devices only) Set the receiver sleep dura- tion (in milliseconds) for 802.11 power saving mode. pppoeac access-concentrator Set the name of the access-concentrator for the pppoe(4) interface. -pppoeac Clear a previously set access-concentrator name. pppoedev parent-interface Set the name of the interface through which pppoe(4) packets will be transmitted and received. pppoesvc service Set the service name of the pppoe(4) interface. -pppoesvc Clear a previously set service name. prefixlen n (inet and inet6 only) Effect is similar to netmask, but you can specify prefix length by digits. range netrange Under AppleTalk, set the interface to respond to a netrange of the form "startnet-endnet". AppleTalk uses this scheme instead of netmasks though OpenBSD implements it internally as a set of netmasks. state state Explicitly force the carp(4) pseudo-device to enter this state. Valid states are init, backup, and master. syncif iface If the driver is a pfsync(4) pseudo-device, use the specified interface to send and receive pfsync state syn- chronisation messages. -syncif If the driver is a pfsync(4) pseudo-device, stop sending pfsync state synchronisation messages over the network. tentative (inet6 only) Set the IPv6 tentative address bit. -tentative (inet6 only) Clear the IPv6 tentative address bit. trailers Request the use of a "trailer" link level encapsulation when sending (default). If a network interface supports trailers, the system will, when possible, encapsulate outgoing messages in a manner which minimizes the number of memory to memory copy operations performed by the re- ceiver. On networks that support ARP (currently, only Ethernet), this flag indicates that the system should re- quest that other systems use trailers when sending to this host. Similarly, trailer encapsulations will be sent to other hosts that have made such requests. Currently used by Internet protocols only. -trailers Disable the use of a "trailer" link level encapsulation. tunnel src_address dest_address Set the source and destination tunnel addresses on a tun- nel 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 ad- dresses must be of the same family. up Mark an interface "up". This may be used to enable an in- terface 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. vhid n If the driver is a carp(4) pseudo-device, set the virtual host ID to n. Acceptable values are 1 to 255. vlan vlan_tag If the interface is a vlan(4) pseudo-interface, 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. Note that vlan and vlandev must both be set at the same time. vlandev iface If the interface is a vlan(4) pseudo-device, associate physical interface iface with it. Packets transmitted through the vlan interface will be diverted to the speci- fied physical interface iface with 802.1Q vlan encapsula- tion. Packets with 802.1Q encapsulation received by the parent interface with the correct vlan tag will be diverted to the associated vlan pseudo-interface. The vlan interface is assigned a copy of the parent interface's flags and the parent's Ethernet address. vlandev and vlan must both be set at the same time. If the vlan interface already has a physical interface asso- ciated with it, this command will fail. To change the as- sociation to another physical interface, the existing as- sociation must be cleared first. Note: if the link0 flag is set on the vlan interface, the vlan pseudo-interface's behavior changes; link0 tells the vlan interface that the parent interface supports inser- tion and extraction of vlan tags on its own (usually in firmware) and that it should pass packets to and from the parent unaltered. -vlandev If the driver is a vlan(4) pseudo-device, disassociate the physical interface from it. This breaks the link between the vlan interface and its parent, clears its vlan tag, flags, and link address, and shuts the inter- face down. vltime n (inet6 only) Set valid lifetime for the address.
Assign the inet(3) 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 Assign the ipx(3) address of 12625920 specified in decimal to interface fxp0: # ifconfig fxp0 ipx 12625920 Assign the AppleTalk network 39108 and server node 128 with a network range of 39107-39109 to interface fxp0 on a phase 2 AppleTalk network: # ifconfig fxp0 atalk 39108.128 range 39107-39109 phase 2 Configure the xl0 interface to use 10baseT: # ifconfig xl0 media 10baseT Configure the xl0 interface to use 100baseTX, full duplex: # ifconfig xl0 media 100baseTX mediaopt full-duplex Configure the vlan0 interface for IP address 192.168.254.1, vlan tag 4, and vlan parent device fxp0: # ifconfig vlan0 192.168.254.1 vlan 4 vlandev fxp0 Configure the carp0 interface for IP address 192.168.10.1, virtual host ID 1: # ifconfig carp0 vhid 1 192.168.10.1 Create the gif1 network interface: # ifconfig gif1 create Destroy the gif1 network interface: # ifconfig gif1 destroy
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.
netstat(1), inet(3), ipx(3), arp(4), bridge(4), carp(4), gif(4), gre(4), ifmedia(4), inet(4), lo(4), netintro(4), pfsync(4), ppp(4), pppoe(4), sl(4), tun(4), vlan(4), hostname.if(5), hosts(5), networks(5), brconfig(8), rc(8), routed(8)
The ifconfig command appeared in 4.2BSD. MirOS BSD #10-current September 3, 1998 6
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