.\"	$NetBSD: ifconfig.if.5,v 1.18.18.1 2020/04/22 17:55:16 martin Exp $
.\"
.\" Copyright (c) 1996 Matthew R. Green
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.Dd April 15, 2020
.Dt IFCONFIG.IF 5
.Os
.Sh NAME
.Nm ifconfig.if
.Nd interface-specific configuration files or variables
.Sh DESCRIPTION
The
.Nm
files or variables contain information regarding the configuration
of each network interface.
.Nm
is processed by
.Pa /etc/rc.d/network
at system boot time.
.Pp
For each interface
.Pq Ar nnX
that is to be configured, there should be either an
.Sy ifconfig_nnX
variable in
.Xr rc.conf 5 ,
or an
.Pa /etc/ifconfig.nnX
file
(such as the
.Sy ifconfig_fxp0
variable or the
.Pa /etc/ifconfig.fxp0
file for the
.Sy fxp0
interface).
Only characters allowed in
.Xr sh 1
variables names should be used for
.Ar nnX
.Po Xr ascii 7
uppercase and lowercase letters, digits, and underscore
.Pc .
.Pp
The variable or file will get evaluated only if the interface exists on
the system.
Multiple lines can be placed in a variable or file, and will be
evaluated sequentially.
In the case of a variable, semicolons may be used instead of
newlines, as described in
.Xr rc.conf 5 .
.Ao backslash Ac Ns Ao newline Ac
sequences in files are ignored, so long logical lines may be
made up of several shorter physical lines.
.Pp
Normally, a line will be evaluated as command line arguments to
.Xr ifconfig 8 .
.Dq Li ifconfig Ar nnX
will be prepended on evaluation.
Arguments with embedded shell metacharacters should be quoted in
.Xr sh 1
style.
.Pp
If the line is equal to
.Dq dhcp ,
.Xr dhcpcd 8
will be started for the interface.
However, it is instead recommended that
.Sy dhcpcd
is set to true in
.Xr rc.conf 5
and any per interface configuration or restriction is done in
.Xr dhcpcd.conf 5 .
.Pp
If a line is empty, or starts with
.Sq # ,
the line will be ignored as comment.
.Pp
If a line starts with
.Sq \&! ,
the rest of line will get evaluated as shell script fragment.
Shell variables declared in
.Pa /etc/rc.d/network
are accessible but may not be modified.
The most useful variable is
.Li $int ,
as it will be bound to the interface being configured with the file.
.Pp
For example, the following illustrates static interface configuration:
.Bd -literal -offset indent
# IPv4, with an alias
inet 10.0.1.12 netmask 255.255.255.0 media 100baseTX
inet 10.0.1.13 netmask 255.255.255.255 alias
# let us have IPv6 address on this interface
inet6 2001:db8::1 prefixlen 64 alias
# have subnet router anycast address too
inet6 2001:db8:: prefixlen 64 alias anycast
.Ed
.Pp
The following example sets a network name for a wireless interface
(using quotes to protect special characters in the name),
and starts
.Xr dhcpcd 8 :
.Bd -literal -offset indent
ssid 'my network'
dhcp
.Ed
.Pp
The following example is for dynamically-created pseudo interfaces like
.Xr gif 4 .
Earlier versions of
.Pa /etc/rc.d/network
required an explicit
.Sq create
command for such interfaces,
but creation is now handled automatically.
.Bd -literal -offset indent
up
# configure IPv6 default route toward the interface
!route add -inet6 default ::1
!route change -inet6 default -ifp $int
.Ed
.Sh FILES
.Pa /etc/rc.d/network
.Sh SEE ALSO
.Xr rc.conf 5 ,
.Xr ifconfig 8