4.3BSD-Reno/share/man/cat8/ifconfig.0
IFCONFIG(8) 1990 IFCONFIG(8)
NNAAMMEE
ifconfig - configure network interface parameters
SSYYNNOOPPSSIISS
iiffccoonnffiigg 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 ]
iiffccoonnffiigg interface [ protocol_family ]
DDEESSCCRRIIPPTTIIOONN
_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'', ``iso'', 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. For the ISO family,
addresses are specified as a long hexadecimal string, as in
the Xerox family. However, two consecutive dots imply a
zero byte, and the dots are optional, if the user wishes to
(carefully) count out long strings of digits in network byte
order.
The following parameters may be set with _i_f_c_o_n_f_i_g:
uupp 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.
ddoowwnn Mark an interface ``down''. When an inter-
face is marked ``down'', the system will not
attempt to transmit messages through that
Printed 7/27/90 June 1
IFCONFIG(8) 1990 IFCONFIG(8)
interface. If possible, the interface will be
reset to disable reception as well. This
action does not automatically disable routes
using the interface.
ttrraaiilleerrss 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.
--ttrraaiilleerrss Disable the use of a ``trailer'' link level
encapsulation.
aarrpp 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.
--aarrpp Disable the use of the Address Resolution
Protocol.
mmeettrriicc _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.
ddeebbuugg Enable driver dependent debugging code; usu-
ally, this turns on extra console error log-
ging.
--ddeebbuugg Disable driver dependent debugging code.
nneettmmaasskk _m_a_s_k (Inet and Iso) 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
Printed 7/27/90 June 2
IFCONFIG(8) 1990 IFCONFIG(8)
field of the address. The mask can be speci-
fied 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 contiguous with the network
portion.
ddeesstt__aaddddrreessss Specify the address of the correspondent on
the other end of a point to point link.
bbrrooaaddccaasstt (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.
iippddsstt This is used to specify an Internet host who
is willing to receive ip packets encapsulat-
ing NS packets bound for a remote network.
An apparent point to point link is con-
structed, and the address specified will be
taken as the NS address and network of the
destination. IP encapsulation of CLNP pack-
ets is done differently, see _e_o_n(5).
aalliiaass 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 inter-
face.
ddeelleettee 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.
nnsseelllleennggtthh _n (ISO only) This specifies a trailing number
of bytes for a received NSAP used for local
identification, the remaining leading part of
which is taken to be the NET (Network Entity
Title). The default value is 1, which is
conformant to US GOSIP. When an iso address
is set in an ifconfig command, it is really
the NSAP which is being specified. For
Printed 7/27/90 June 3
IFCONFIG(8) 1990 IFCONFIG(8)
example, in US GOSIP, 20 hex digits should be
specified in the ISO NSAP to be assigned to
the interface. There is some evidence that a
number different 1 may be useful for AFI 37
type addresses.
_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.
DDIIAAGGNNOOSSTTIICCSS
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.
SSEEEE AALLSSOO
netstat(1), netintro(4), rc(8), routed(8), eon(5)
Printed 7/27/90 June 4