ifconfig - configure a network interface

       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 dotted
       decimal notation may be decimal, octal, or hexadecimal, as specified in the ISO C standard  (that  is,  a
       leading  0x  or  0X implies hexadecimal; 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.

       Fred N. van Kempen, <waltje@uwalt.nl.mugnet.org>
       Alan Cox, <Alan.Cox@linux.org>
       Phil Blundell, <Philip.Blundell@pobox.com>
       Andi Kleen
       Bernd Eckenfels, <net-tools@lina.inka.de>

net-tools                                          2008-10-03                                        IFCONFIG(8)

       Ifconfig uses the ioctl access method  to  get  the  full  address  information,  which  limits  hardware
       addresses  to  8  bytes.   Because  Infiniband  hardware address has 20 bytes, only the first 8 bytes are
       displayed correctly.  Please use iplink 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.

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
       needed.

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

/proc/net/dev/proc/net/if_inet6

       ifconfig - configure a network interface

       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.

       Interrupt problems with Ethernet device drivers fail  with  EAGAIN  (SIOCSIIFLAGS:Resourcetemporarilyunavailable)  it  is  most likely a interrupt conflict. See http://www.scyld.com/expert/irq-conflict.html
       for more information.

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

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

       -v     be more verbose for some error conditions

       interface
              The  name  of the interface.  This is usually a driver name followed by a unit number, for example
              eth0 for the first Ethernet interface. If your kernel supports alias interfaces, you  can  specify
              them  with  syntax  like  eth0:0  for  the  first  alias  of eth0. You can use them to assign more
              addresses. To delete an alias interface use ifconfigeth0:0down.  Note:  for  every  scope  (i.e.
              same  net  with  address/netmask  combination)  all  aliases  are deleted, if you delete the first
              (primary).

       up     This flag causes the interface to be activated.  It is  implicitly  specified  if  an  address  is
              assigned  to  the  interface;  you  can  suppress  this  behavior when using an alias interface by
              appending an - to the alias (e.g.  eth0:0-).  It is also suppressed when using  the  IPv4  0.0.0.0
              address as the kernel will use this to implicitly delete alias interfaces.

       down   This flag causes the driver for this interface to be shut down.

       [-]arp Enable or disable the use of the ARP protocol on this interface.

       [-]promisc
              Enable  or disable the promiscuous mode of the interface.  If selected, all packets on the network
              will be received by the interface.

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

       mtuN  This parameter sets the Maximum Transfer Unit (MTU) of an interface.

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

       netmaskaddr
              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.

       addaddr/prefixlen
              Add an IPv6 address to an interface.

       deladdr/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 destination.

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

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

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

       mediatype
              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.

       [-]pointopoint[addr]
              This keyword enables the point-to-point mode of an interface, meaning that it  is  a  direct  link
              between two machines with nobody else listening on it.
              If  the  address  argument  is also given, set the protocol address of the other side of the link,
              just like the obsolete dstaddr keyword does.  Otherwise, set or clear the IFF_POINTOPOINT flag for
              the interface.

       hwclassaddress
              Set the hardware address of this interface, if the device driver  supports  this  operation.   The
              keyword  must  be followed by the name of the hardware class and the printable ASCII equivalent of
              the hardware address.  Hardware classes currently supported include ether (Ethernet),  ax25  (AMPR
              AX.25), ARCnet and netrom (AMPR NET/ROM).

       multicast
              Set the multicast flag on the interface. This should not normally be needed as the drivers set the
              flag correctly themselves.

       address
              The IP address to be assigned to this interface.

       txqueuelenlength
              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.

       namenewname
              Change the name of this interface to newname. The interface must be shut down first.

route(8), netstat(8), arp(8), rarp(8), iptables(8), ifup(8), interfaces(5)
       http://physics.nist.gov/cuu/Units/binary.html - Prefixes for binary multiples

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