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       ifconfig [-v] [-a] [-s] [interface]
       ifconfig [-v] interface [aftype] options | address ...


       This  program  is obsolete!  For replacement check ip addr and ip link.
       For statistics use ip -s link.


       Ifconfig is used to configure the kernel-resident  network  interfaces.
       It is used at boot time to set up interfaces as necessary.  After that,
       it is usually only needed when  debugging  or  when  system  tuning  is

       If  no  arguments  are  given, ifconfig displays the status of the cur-
       rently active interfaces.  If a single interface argument is given,  it
       displays  the  status of the given interface only; if a single -a argu-
       ment is given, it displays the status of  all  interfaces,  even  those
       that are down.  Otherwise, it configures an interface.

Address Families

       If  the  first  argument  after the interface name is recognized as the
       name of a supported address family, that address  family  is  used  for
       decoding  and  displaying  all protocol addresses.  Currently supported
       address families include inet (TCP/IP,  default),  inet6  (IPv6),  ax25
       (AMPR  Packet  Radio),  ddp  (Appletalk  Phase 2), ipx (Novell IPX) and
       netrom (AMPR Packet radio).  All numbers supplied as parts in IPv4 dot-
       ted  decimal  notation may be decimal, octal, or hexadecimal, as speci-
       fied in the ISO C standard (that is, a leading 0x or 0X  implies  hexa-
       decimal;  otherwise, a leading '0' implies octal; otherwise, the number
       is interpreted as decimal). Use of hexadecimal and octal numbers is not
       RFC-compliant and therefore its use is discouraged.


       -a     display  all  interfaces  which are currently available, even if

       -s     display a short list (like netstat -i)

       -v     be more verbose for some error conditions

              The name of the interface.  This is usually a driver  name  fol-
              lowed  by a unit number, for example eth0 for the first Ethernet
              interface. If your kernel supports  alias  interfaces,  you  can
              specify  them  with  eth0:0 for the first alias of eth0. You can
              use them to assign a second address. To delete an  alias  inter-
              face use ifconfig eth0:0 down.  Note: for every scope (i.e. same
              net with address/netmask combination) all aliases  are  deleted,

              Enable or disable all-multicast mode.  If selected,  all  multi-
              cast packets on the network will be received by the interface.

       mtu N  This parameter sets the Maximum Transfer Unit (MTU) of an inter-

       dstaddr addr
              Set the remote IP address for a  point-to-point  link  (such  as
              PPP).  This keyword is now obsolete; use the pointopoint keyword

       netmask addr
              Set the IP network mask for this interface.  This value defaults
              to  the  usual class A, B or C network mask (as derived from the
              interface IP address), but it can be set to any value.

       add addr/prefixlen
              Add an IPv6 address to an interface.

       del addr/prefixlen
              Remove an IPv6 address from an interface.

       tunnel ::aa.bb.cc.dd
              Create a new SIT (IPv6-in-IPv4) device, tunnelling to the  given

       irq addr
              Set the interrupt line used by this device.  Not all devices can
              dynamically change their IRQ setting.

       io_addr addr
              Set the start address in I/O space for this device.

       mem_start addr
              Set the start address for shared memory  used  by  this  device.
              Only a few devices need this.

       media type
              Set  the  physical port or medium type to be used by the device.
              Not all devices can change this setting, and those that can vary
              in  what  values  they  support.   Typical  values  for type are
              10base2 (thin Ethernet), 10baseT (twisted-pair 10Mbps Ethernet),
              AUI  (external  transceiver) and so on.  The special medium type
              of auto can be used to tell the driver to auto-sense the  media.
              Again, not all drivers can do this.

       [-]broadcast [addr]
              If  the  address  argument  is given, set the protocol broadcast
              address for this  interface.   Otherwise,  set  (or  clear)  the
              IFF_BROADCAST flag for the interface.

              include ether (Ethernet), ax25 (AMPR AX.25), ARCnet  and  netrom
              (AMPR NET/ROM).

              Set  the  multicast  flag on the interface. This should not nor-
              mally be needed as the drivers  set  the  flag  correctly  them-

              The IP address to be assigned to this interface.

       txqueuelen length
              Set the length of the transmit queue of the device. It is useful
              to set this to small values  for  slower  devices  with  a  high
              latency  (modem links, ISDN) to prevent fast bulk transfers from
              disturbing interactive traffic like telnet too much.


       Since kernel release 2.2 there are no explicit interface statistics for
       alias  interfaces  anymore.  The  statistics  printed  for the original
       address are shared with all alias addresses on the same device. If  you
       want  per-address  statistics  you should add explicit accounting rules
       for the address using the iptables(8) command.

       Since net-tools 1.60-4 ifconfig is printing  byte  counters  and  human
       readable counters with IEC 60027-2 units. So 1 KiB are 2^10 byte. Note,
       the numbers are truncated to one decimal (which can by  quite  a  large
       error if you consider 0.1 PiB is 112.589.990.684.262 bytes :)

       Interrupt problems with Ethernet device drivers fail with EAGAIN (SIOC-
       SIIFLAGS: Resource temporarily unavailable) it is most likely a  inter-
       rupt  conflict.  See  http://www.scyld.com/expert/irq-conflict.html for
       more information.




       Ifconfig uses the ioctl access method to get the full address  informa-
       tion,  which  limits hardware addresses to 8 bytes.  Because Infiniband
       hardware address has 20 bytes, only the first  8  bytes  are  displayed
       correctly.  Please use ip link command from iproute2 package to display
       link layer informations including the hardware address.

       While appletalk DDP and IPX addresses will be displayed they cannot  be
       altered by this command.


       ip(8), iptables(8)
       http://physics.nist.gov/cuu/Units/binary.html  -  Prefixes  for  binary
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