Manual browser: ifconfig.if(5)

IFCONFIG.IF(5) File Formats Manual IFCONFIG.IF(5)


ifconfig.ifinterface-specific configuration files or variables


The ifconfig.if files or variables contain information regarding the configuration 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, and underscore).

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. Arguments 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 in dhcpcd.conf(5).

If a line is empty, or starts with ‘#’, the line will be ignored as comment.

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 netmask media 100baseTX 
inet netmask 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 illustrates dynamic configuration setup with dhclient(8) and rtsol(8):

# autoconfigure IPv4 address 
!dhclient $int 
# autoconfigure IPv6 address.  Be sure to set $ip6mode to autohost. 
!rtsol $int

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 automatically.

# configure IPv6 default route toward the interface 
!route add -inet6 default ::1 
!route change -inet6 default -ifp $int


October 2, 2012 NetBSD 7.0