.Dd July 4, 2021
.Dt IFCONFIG 8
.Os
.Sh NAME
.Nm ifconfig
.Nd configure network interface
.Sh SYNOPSIS
.Nm
.Op Ar interface
.Nm
.Ar interface
.Oo
.Ar protocol
.Op Ar configuration Ar new-value ...
.Ar ...
.Oc
.Nm
.Fl l
.Oo Ar interface Oo Ar protocol Oo Ar configuration Oc Oc Oc
.Nm
.Fl l
.Ar interface
.Ar protocol
.Op Ar configuration ...
.Ar ...
.Sh DESCRIPTION
.Nm
can both write the current configuration of
.Xr if 4
network interface devices as well as update the configuration of a network
interface.
By default the configuration of every network interface is written.
If the
.Ar interface
argument is given, only the configuration of that network interface is
written.
.Pp
If an
.Ar interface
is specified along with further operands, the configuration of the network
interface is updated by iterating over the remaining operands:
Naming a
.Ar protocol
makes it the current protocol, naming a
.Ar configuration
sets it within the current protocol to the subsequent
.Ar new-value
operand.
.Pp
The options are as follows:
.Bl -tag -width "12345678"
.It Fl l
Write the current value of each specified
.Ar configuration
rather than setting a new value.
The
.Ar new-value
argument is no longer passed.
.Pp
If only an
.Ar interface
and a
.Ar protocol
is specified, list the names of each configuration of that protocol on the
network interface.
.Pp
If only an
.Ar interface
is specified, list the names of each protocol on the network interface.
.Pp
If no
.Ar interface
is specified, list the names of each network interface.
.El
.Pp
The
.Ar interface
argument can be the name or the path of an interface, or a specifier uniquely
matching an interface:
.Pp
.Bl -tag -width "12345678901" -compact
.It Sy ether : Ns Ar mac
Local
.Xr ether 4
address.
.It Sy etherhw : Ns Ar mac
Hardware
.Xr ether 4
address.
.It Sy inet : Ns Ar ip
Local
.Xr inet 4
address.
.It Sy id : Ns Ar num
Network interface integer index.
.El
.Pp
The
.Cm link
.Ar protocol
provides information about the network interface.
The following configurations are supported:
.Pp
.Bl -tag -width "12345678901" -compact
.It Cm up
.Sy yes
if the link is up and
.Sy no
otherwise.
(read-only)
.It Cm type
The type of the network interface, either
.Sy ether
or
.Sy loopback .
(read-only)
.It Cm id
The network interface integer index.
(read-only)
.It Cm name
The name of the network interface.
(read-only)
.El
.Pp
The
.Cm loopback
.Ar protocol
.Pq Xr lo 4
has no configuration.
.Pp
The
.Cm ether
.Ar protocol
.Pq Ethernet , Xr ether 4
has the following configurations:
.Pp
.Bl -tag -width "12345678901" -compact
.It Cm address
The local address in
.Xr ether 4
address notation, or
.Sy default
to use the hardware address.
.It Cm hwaddress
The hardware address in
.Xr ether 4
address notation.
(read-only)
.El
.Pp
The
.Cm inet
.Ar protocol
.Pq  Internet Protocol version 4 , Xr inet 4
has the following configurations:
.Pp
.Bl -tag -width "12345678901" -compact
.It Cm address
The local address in
.Xr inet 4
address notation.
.It Cm router
The default route in
.Xr inet 4
address notation.
.It Cm subnet
The subnet mask in
.Xr inet 4
address notation.
.El
.Sh EXIT STATUS
.Nm
will exit 0 on success and non-zero otherwise.
.Sh EXAMPLES
.Bd -literal
$ ifconfig
if0:
	link up yes type ether id 2
	ether address 00:00:5e:00:53:ff hwaddress 00:00:5e:00:53:ff
	inet address 192.0.2.2 router 192.0.2.1 subnet 255.255.255.0
lo0:
	link up yes type loopback id 1
	loopback
	inet address 127.0.0.1 router 0.0.0.0 subnet 255.0.0.0
$ ifconfig if0
if0:
	link up yes type ether id 2
	ether address 00:00:5e:00:53:ff hwaddress 00:00:5e:00:53:ff
	inet address 192.0.2.2 router 192.0.2.1 subnet 255.255.255.0
$ ifconfig if0 inet address 198.51.100.2 router 198.51.100.1
$ ifconfig if0 ether address 00:00:5e:00:53:42 inet address 198.51.100.3
$ ifconfig -l
if0
lo0
$ ifconfig -l if0
link
ether
inet
$ ifconfig -l if0 inet
address
router
subnet
$ ifconfig -l if0 inet address
198.51.100.3
$ ifconfig -l if0 inet address subnet ether address link id
198.51.100.3
255.255.255.0
00:00:5e:00:53:42
42
$ ifconfig -l etherhw:00:00:5e:00:53:ff link name
if0
.Ed
.Sh SEE ALSO
.Xr ether 4 ,
.Xr if 4 ,
.Xr inet 4 ,
.Xr lo 4 ,
.Xr dhclient 8 ,
.Xr dnsconfig 8
.Sh CAVEATS
.Xr ether 4
network interfaces with the
.Xr inet 4
protocol are commonly automatically configured by
.Xr dhclient 8 .
Disable
.Xr dhclient 8
before manually configuring
.Xr inet 4
on such interfaces to avoid the manual configuration being overwritten, or
configure
.Xr dhclient 8
to set your desired network interface configuration in the first place.