# s_n_d(8)

## NAME

         s_n_d, set_net_default - select the default TCP/IP network

## SYNOPSIS

         set_net_default: not found

## DESCRIPTION

         This manual page is here  because  so  many  others  refer  to  it.   The
         set_net_default  command does not exist under standard Minix, because the
         TCP/IP server only supports one  network.   The  server  under  Minix-vmd
         supports  four different networks, that can each be chosen as the default
         network.

         The TCP/IP library and  commands  do  have  a  notion  about  a  "default
         network"  however, because the code is shared between the Minix versions.
         So if you want to venture into network programming then you  should  know
         about  the devices and environment variables mentioned below to make your
         program compatible.  (Especially since there is a  plan  to  upgrade  the
         TCP/IP server for standard Minix.)

      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 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.

         ETH_DEVICE=device
         -E device
              Device to  use  as  raw  ethernet  device  instead  of  the  default
              /dev/eth.

         PSIP_DEVICE=device
         -P device
              Pseudo IP device to use instead of /dev/psip.

         IP_DEVICE=device
         -I device
              IP device to use instead of /dev/ip.

         TCP_DEVICE=device
         -T device
              TCP device to use.

         UDP_DEVICE=device
         -U device
              UDP device to use.

## FILES

         /dev/eth[01]      First and second raw ethernet.

         /dev/psip[01]     First and second Pseudo IP network.

         /dev/ip[0123]     IP  devices  for  two  ethernets  and  two  Pseudo   IP
                           networks.

         /dev/tcp[0123]    TCP devices for same four networks.

         /dev/udp[0123]    UDP devices.

         /dev/eth, /dev/psip, /dev/ip, /dev/tcp, /dev/udp
                           Devices for the default network, links to  the  devices
                           above.  Eth is only present if ethernet is the default,
                           psip only for pseudo IP.

## SEE ALSO

         ip(4), boot(8).

## AUTHOR

         Kees J. Bot (kjb@cs.vu.nl)