PPPD DEMAND OPTION
By: David Efflandt tech@de-srv.com
Based on news posting of: Les Hazelton

There do not appear to be detailed instructions or example of how to use
demand dialing ppp with the pppd package.  I was previously using diald in
RedHat 5.2, but had trouble getting it to work in RedHat 6.1.  So this is
information I got from a news post of Les Hazelton about using the pppd
demand option, modified for my use, and it works in RedHat Linux 6.1.  One
disadvantage of ppp demand dialing is that it does not have the control
and monitoring pipes that can be used with diald.

Note: Attempting to use a manual pppd connection on the same modem while
pppd is already running in demand mode will not work (likewise if diald is
running).  Without a more elegant solution 'killall pppd' will kill the
demand pppd.  For diald see 'man diald' and related man pages about
controlling it.

Does anyone know why command line switches for following do not work if I
change them to single dash like "-c"?  If I do, bash complains that binary
modifier is missing in the first if statement.  Single dashes worked in
Linux for Les Hazelton who I derived this from.

--- /usr/sbin/ppp-auto ---

#!/bin/sh
if [ "$1" = "--c" ]; then
killall pppd 2>/dev/null
case `ps x` in
        pppd) sleep 1;;
esac
rm -f /var/lock/LCK..* /var/run/ppp*.pid
rm -f /etc/ppp/report-chat
sleep 1

# Use real IP's in following (or best guess):
(/usr/sbin/pppd 10.0.0.1:10.0.0.2 call isp connect \
"/usr/sbin/chat -v -r /etc/ppp/report-chat -f /etc/ppp/ppp.chatscript") \
|| exit 1

# Use real domain and nameserver IP's in following
echo "domain isp.con" > /etc/resolv.conf
echo "nameserver 192.168.1.34" >> /etc/resolv.conf
echo "nameserver 192.168.1.35" >> /etc/resolv.conf
echo "Enabled passive on demand ppp"
exit 0

elif [ "$1" = "--l" ]; then
clear 2>/dev/null
tail -n 24 /var/log/messages | cut -d' ' -f5- | tr -d ^M
exit 0
fi

echo "Command was: $0 $@"
echo "USAGE: ppp-auto --c  <Make PPP connection>"
echo "       ppp-auto --l  <Show last 24 messages from /var/log/messages>"
echo "                     <Useful if ppp-auto --c fails>"
# last line


--- /etc/ppp/ppp.chatscript

TIMEOUT 10
ABORT ERROR
ABORT BUSY
ABORT "NO CARRIER"
ABORT "NO DIALTONE"
REPORT CONNECT
"" "ATZ"
OK "ATDT555-1212"
TIMEOUT 60
CONNECT


--- /etc/ppp/peers/isp ---

/dev/ttyS0
115200
crtscts
defaultroute
lock
passive
demand
hide-password
idle 900
ipcp-accept-local
ipcp-accept-remote
noipdefault
asyncmap a0000
name ppp0
user efflandt
ipparam isp.com
usepeerdns
# end of options

Note: This uses existing pap-secrets for 'ppp0' connection set up with
the netcfg tool in RedHat.

The ipparam and usepeerdns is used by ip-up.local to set /etc/resolv.conf
with the domain name ($6) and nameservers ($DNS1, $DNS2) when it actually 
dials out.


--- /etc/ppp/ip-up.local (or ip-up on non-RedHat) ---

#!/bin/bash
# The  environment is cleared before executing this script
# so the path must be reset
PATH=/usr/sbin:/sbin:/usr/bin:/bin
export PATH

case $6 in
# LAN connection (no DNS)
my-lan )
	echo "search" > /etc/resolv.conf
	sleep 1
	/sbin/route add -net 192.168.0.0 netmask 255.255.0.0 $1;;
# ISP
isp.com | compuserve.com )
	echo "domain $6" > /etc/resolv.conf
	echo "nameserver $DNS1" >> /etc/resolv.conf
	if [ $DNS2 ] ; then
		echo "nameserver $DNS2" >> /etc/resolv.conf
	fi
	sleep 1;;
esac
# last line