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IFCONFIG.IF(5) NetBSD File Formats Manual IFCONFIG.IF(5)
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ifconfig.if -- interface-specific configuration files or variables
The ifconfig.if files or variables contain information regarding the con-
figuration of each network interface. ifconfig.if is processed by
/etc/rc.d/network at system boot time.
For each interface (nnX) that is to be configured, there should be either
an ifconfig_nnX variable in rc.conf(5), or an /etc/ifconfig.nnX file
(such as the ifconfig_fxp0 variable or the /etc/ifconfig.fxp0 file for
the fxp0 interface). Only characters allowed in sh(1) variables names
should be used for nnX (ascii(7) uppercase and lowercase letters, digits,
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 rc.conf(5).
<backslash><newline> sequences in files are ignored, so long logical
lines may be made up of several shorter physical lines.
Normally, a line will be evaluated as command line arguments to
ifconfig(8). ``ifconfig nnX'' will be prepended on evaluation. Argu-
ments with embedded shell metacharacters should be quoted in sh(1) style.
If the line is equal to ``dhcp'', dhcpcd(8) will be started for the
interface. However, it is instead recommended that dhcpcd is set to true
in rc.conf(5) and any per interface configuration or restriction is done
If a line is empty, or starts with `#', the line will be ignored as com-
If a line starts with `!', the rest of line will get evaluated as shell
script fragment. Shell variables declared in /etc/rc.d/network are
accessible but may not be modified. The most useful variable is $int, as
it will be bound to the interface being configured with the file.
For example, the following illustrates static interface configuration:
# 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
The following example sets a network name for a wireless interface (using
quotes to protect special characters in the name), and starts dhcpcd(8):
ssid 'my network'
The following example is for dynamically-created pseudo interfaces like
gif(4). Earlier versions of /etc/rc.d/network required an explicit
`create' command for such interfaces, but creation is now handled auto-
# configure IPv6 default route toward the interface
!route add -inet6 default ::1
!route change -inet6 default -ifp $int
NetBSD 9.1 April 15, 2020 NetBSD 9.1