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Title: ISDN: Switch on/off dial on demand

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ISDN: Switch on/off dial on demand

Question:

The i4l subsystem keeps on dialing automatically. Where and how can this be triggered?

Answer:

Dial on demand means that a connection is established automatically if there are IP packets waiting for this connection. If nothing happens for a certain amount of time the connection is closed.

The i4l subsystem has not been designed for being started manually. Or you could say that it provides a permanent connection which is closed if nothing happens.

For those of you who don't like this behaviour there is a means of starting and stopping the i4l system manually. This may be achieved by entering: /sbin/init.d/i4l start (or stop respectively). Please don't forget to start route start after the i4l subsystem has been activated.

It is much mor comfortable if you design the runlevels accordingly. The i4l subsystem is activated in runlevels 2 and 3 by default (same as the local net). Well you my reserve runlevel 3 for i4l. This would make it easy to switch it on by entering init 2 and init 3 respectively.

More on this topic may be found in our handbook. Here we list just the scripts you will need:

You should deactivate xdm in runlevel 3.

There is a nice tool for maintaining runlevels: rctab

Since it should be sufficient just to set the default route there is another method by Glen Reiff (reiff@sdm.de):

#!/bin/sh
# Activate/Deactivate dial on demand 
# 14.1.98 by Glen Reiff (reiff@sdm.de)
# small changes by kfr@suse.de, 16.01.98

NETDEV="ippp0"

case "$1" in

start)
  Default=`netstat -rn | grep $NETDEV | cut -d " " -f 1|grep -v 0.0.0.0`
  /sbin/route add default gw $Default
  ;;

stop)
  /sbin/route del default
  /sbin/isdnctrl hangup $NETDEV
  ;;

*)
  echo "Usage: $0 {start|stop}"
  exit 1
  ;;

esac

Hint: You may set the permissions for this script (setuid bit, see man man chmod) for everybody in this group to start and stop the connection manually.

Well, it is even better to make sure that connections are only established if they're needed. This makes it easier for the mail and news polls that can be done during the night. See various articles on this topic in the SDB

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Keywords: ISDN, DIAL, DEMAND, RUNLEVEL, ISDNBUTTON

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SDB-i4l_dialondemand, Copyright SuSE GmbH, Nuremberg, Germany - Version:
SuSE GmbH - Last generated: 07. Oct 1999 16:41:15 by maddin with sdb_gen 1.00.0