4.3BSD-UWisc/man/cat8/ifconfig.8c
IFCONFIG(8C) UNIX Programmer's Manual IFCONFIG(8C)
NAME
ifconfig - configure network interface parameters
SYOPNSIS
/etc/ifconfig interface address_family [ _a_d_d_r_e_s_s [
_d_e_s_t__a_d_d_r_e_s_s ] ] [ _p_a_r_a_m_e_t_e_r_s ]
/etc/ifconfig interface [ protocol_family ]
DESCRIPTION
_I_f_c_o_n_f_i_g is used to assign an address to a network interface
and/or configure network interface parameters. _I_f_c_o_n_f_i_g
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. The _i_n_t_e_r_f_a_c_e parameter is a string
of the form ``name unit'', e.g. ``en0''.
Since an interface may receive transmissions in differing
protocols, each of which may require separate naming
schemes, it is necessary to specify the _a_d_d_r_e_s_s__f_a_m_i_l_y,
which may change the interpretation of the remaining parame-
ters. The address families currently supported are ``inet''
and ``ns''.
For the DARPA-Internet family, the address is either a host
name present in the host name data base, _h_o_s_t_s(5), or a
DARPA Internet address expressed in the Internet standard
``dot notation''. For the Xerox Network Systems(tm) family,
addresses are _n_e_t:_a._b._c._d._e._f, where _n_e_t is the assigned
network number (in decimal), and each of the six bytes of
the host number, _a through _f, are specified in hexadecimal.
The host number may be omitted on 10Mb/s Ethernet inter-
faces, which use the hardware physical address, and on
interfaces other than the first.
The following parameters may be set with _i_f_c_o_n_f_i_g:
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.
down Mark an interface ``down''. When an inter-
face 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.
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IFCONFIG(8C) UNIX Programmer's Manual IFCONFIG(8C)
trailers Request the use of a ``trailer'' link level
encapsulation when sending (default). If a
network interface supports _t_r_a_i_l_e_r_s, the sys-
tem will, when possible, encapsulate outgoing
messages in a manner which minimizes the
number of memory to memory copy operations
performed by the receiver. On networks that
support the Address Resolution Protocol (see
_a_r_p(4P); currently, only 10 Mb/s Ethernet),
this flag indicates that the system should
request 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.
arp Enable the use of the Address Resolution Pro-
tocol in mapping between network level
addresses and link level addresses (default).
This is currently implemented for mapping
between DARPA Internet addresses and 10Mb/s
Ethernet addresses.
-arp Disable the use of the Address Resolution
Protocol.
subarp Enable an interface on a subnet gateway to
respond to ARP requests for hosts reachable
via this subnet. Only useful on hardware
which supports ARP. This allows a gateway
between two subnets to respond to ARP
requests received on an enabled interface to
respond for hosts on another enabled inter-
face and route packets thru the gateway.
This allows a network configuration where
only the gateway hosts need to be aware of
the existence of subnets.
-subarp Disable the ARP subnet code
metric _n Set the routing metric of the interface to _n,
default 0. The routing metric is used by the
routing protocol (_r_o_u_t_e_d(8c)). Higher
metrics have the effect of making a route
less favorable; metrics are counted as addi-
tion hops to the destination network or host.
debug Enable driver dependent debugging code; usu-
ally, this turns on extra console error
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IFCONFIG(8C) UNIX Programmer's Manual IFCONFIG(8C)
logging.
-debug Disable driver dependent debugging code.
netmask _m_a_s_k (Inet only) Specify how much of the address
to reserve for subdividing networks into
sub-networks. 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 _n_e_t_w_o_r_k_s(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 con-
tiguous with the network portion.
dstaddr Specify the address of the correspondent on
the other end of a point to point link.
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.
ipdst (NS only) This is used to specify an Internet
host who is willing to receive ip packets
encapsulating NS packets bound for a remote
network. In this case, an apparent point to
point link is constructed, and the address
specified will be taken as the NS address and
network of the destinee.
_I_f_c_o_n_f_i_g 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 super-user may modify the configuration of a net-
work interface.
DIAGNOSTICS
Messages indicating the specified interface does not exit,
the requested address is unknown, or the user is not
privileged and tried to alter an interface's configuration.
SEE ALSO
netstat(1), intro(4N), rc(8)
Printed 12/27/86 May 22, 1986 3