The "ifconfig" command allows the operating
system to setup network interfaces and allow the user to view
information about the configured network interfaces.
| address |
For the DARPA-Internet family, the
address is either a host name present in the host name data
base, or a DARPA Internet address expressed in the Internet
standard ``dot notation''.
It is also possible to use the CIDR notation (also known as
the slash notation) to include the netmask. That is, one can
specify an address like 192.168.0.1/16.
|
| addres_family |
Specify 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'', ``inet6'', |
| dest_address |
Specify the address of the
correspondent on the other end of a point to point link. |
| interface |
This parameter is a string of the
form ``name unit'', for example, ``en0''. |
| add |
Another name for the alias
parameter. Introduced for compatibility with BSD/OS. |
| 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. If the address is on the same
subnet as the first network address for this interface, a
netmask of 0xffffffff has to be specified. |
| -alias |
Remove the network address
specified. This would be used if you incorrectly specified an
alias, or it was no longer needed. If you have incorrectly set
an NS address having the side effect of specifying the host
portion, removing all NS addresses will allow you to respecify
the host portion. |
| anycast |
(Inet6 only.) Specify that the
address configured is an anycast address. Based on the current
specification, only routers may configure anycast addresses.
Anycast address will not be used as source address of any of
outgoing IPv6 packets. |
| arp |
Enable the use of the Address
Resolution Protocol in mapping between network level addresses
and link level addresses (default). This is currently
implemented for mapping between DARPA Internet addresses and
IEEE 802 48-bit MAC addresses (Ethernet, FDDI, and Token Ring
addresses). |
| -arp |
Disable the use of the Address
Resolution Protocol |
| broadcast |
(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. |
| debug |
Enable driver dependent debugging
code; usually, this turns on extra console error logging. |
| -debug |
Disable driver dependent debugging
code. |
| delete |
Another name for the -alias
parameter. |
| 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 does not automatically disable routes using the
interface. |
| ether |
Another name for the lladdr
parameter. |
| lladdr addr |
Set the link-level address on an
interface. This can be used to e.g. set a new MAC address on an
ethernet interface, though the mechanism used is not ethernet-specific.
The address addr is specified as a series of
colon-separated hex digits. If the interface is already up when
this option is used, it will be briefly brought down and then
brought backup again in order to ensure that the receive filter
in the underlying ethernet hardware is properly reprogrammed. |
| media type |
If the driver supports the media
selection system, set the media type of the interface to type.
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/AUI''
would change the currently active connector to the AUI port.
Setting it to ``10baseT/UTP'' would activate twisted pair. Refer
to the interfaces' driver specific documentation or man page for
a complete list of the available types. |
| -mediaopt opts |
If the driver supports the media
selection system, set the specified media options on the
interface. The opts argument is a comma delimited list of
options to apply to the interface. Refer to the interfaces'
driver specific man page for a complete list of available
options. |
| tunnel src_addr
dest_addr |
(IP tunnel devices only.) Configure
the physical source and destination address for IP tunnel
interfaces. The arguments src_addr and dest_addr
are interpreted as the outer source/destination for the
encapsulating IPv4/IPv6 header. |
| deletetunnel |
Unconfigure the physical source and
destination address for IP tunnel interfaces previously
configured with tunnel. |
| create |
Create the specified network
pseudo-device. If the interface is given without a unit number,
try to create a new device with an arbitrary unit number. If
creation of an arbitrary device is successful, the new device
name is printed to standard output. |
| destroy |
Destroy the specified network
pseudo-device. |
| plumb |
Another name for the create
parameter. Included for Solaris compatibility. |
| unplumb |
Another name for the destroy
parameter. Included for Solaris compatibility. |
| metric n |
Set the routing metric of the
interface to n, default 0. The routing metric is used by
the routing protocol. Higher metrics have the effect of making a
route less favorable; metrics are counted as addition hops to
the destination network or host. |
| mtu n |
Set the maximum transmission unit
of the interface to n, default is interface specific. The
MTU is used to limit the size of packets that are transmitted on
an interface. Not all interfaces support setting the MTU, and
some interfaces have range restrictions. |
| netmask mask |
(Inet only.) 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. 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. The netmask can also be specified in CIDR
notation after the address. See the address option above
for more information. |
| prefixlen len |
(Inet6 only.) Specify that len
bits are reserved for subdividing networks into sub-networks.
The len must be integer, and for syntactical reason it
must be between 0 to 128. It is almost always 64 under the
current IPv6 assignment rule. If the parameter is omitted, 64 is
used. |
| remove |
Another name for the -alias
parameter. Introduced for compatibility with BSD/OS. |
| link[0-2] |
Enable special processing of the
link level of the interface. These three options are interface
specific in actual effect, how- ever, 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. |
| -link[0-2] |
Disable special processing at the
link level with the specified interface. |
| 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. |
View the network settings on
the first Ethernet adapter installed in the computer.
Display into on all network interfaces on server,
active or inactive.
If eth0 exists would take it down causing it cannot
send or receive any information.
If eth0 exists and in the down state would return it
back to the up state allowing to to send and receive information.
