.TH SET_NET_DEFAULT 8
.SH NAME
set_net_default \- select the default TCP/IP network
.SH SYNOPSIS
.B set_net_default
.I sample-device
.SH DESCRIPTION
.B Set_net_default
selects the default network to use of one of the four networks a Minix
system can be connected to.  One can choose between two different ethernet
networks and two different pseudo IP networks that can be used to make a
connection over a serial line.
.PP
The
.I sample-device
is the name of one of the network devices in
.B /dev
to use as the default network.  This device and devices for other protocols
for the same network will be linked to the default device names for the
network.  The network utilities access the default network through these
devices, unless a different device is chosen by setting an environment
variable, or a by a command line switch.
.SS "Options and environment to change the default"
Many TCP/IP programs implement the following options and environment
variables to change the default devices set by
.BR set_net_default .
The options are only implemented for low level programs where it makes sense
to name a network device.  The environment variables are used in all code.
You can run a process and all its children connected to a different network
by setting four environment variables.
.PP
.BI ETH_DEVICE= device
.br
.BI -E " device"
.RS
Device to use as raw ethernet device instead of the default /dev/eth.
.RE
.PP
.BI PSIP_DEVICE= device
.br
.BI -P " device"
.RS
Pseudo IP device to use instead of /dev/psip.
.RE
.PP
.BI IP_DEVICE= device
.br
.BI -I " device"
.RS
IP device to use instead of /dev/ip.
.RE
.PP
.BI TCP_DEVICE= device
.br
.BI -T " device"
.RS
TCP device to use.
.RE
.PP
.BI UDP_DEVICE= device
.br
.BI -U " device"
.RS
UDP device to use.
.RE
.SH FILES
.IP /dev/eth[01] 18n
First and second raw ethernet.
.IP /dev/psip[01]
First and second Pseudo IP network.
.IP /dev/ip[0123]
IP devices for two ethernets and two Pseudo IP networks.
.IP /dev/tcp[0123]
TCP devices for same four networks.
.IP /dev/udp[0123]
UDP devices.
.IP "/dev/eth, /dev/psip, /dev/ip, /dev/tcp, /dev/udp"
Devices for the default network, links to the devices above.
.B Eth
is only present if ethernet is the default,
.B psip
only for pseudo IP.
.SH "SEE ALSO"
.BR ip (4),
.BR boot (8).
.SH AUTHOR
Kees J. Bot (kjb@cs.vu.nl)