Dod checking ppp initiator

Hie guys
 
I have configured a dial on demand Redhat Linux servers for Redhat 7.0 up to 9 for my clients. I am however frequently having problems with the clients querying the times thier server get connected since no one will be in the office say between 2 and 4 a.m.
 
What i am still trying to establish is what is it that brings up the dialing at such odd hours yet i would have confgure a cron job as below:
 
00 07-17 * * 1-5 /etc/ppp/mailstart
00 12 * * 1-5 /etc/ppp/mailstart
00 00-23/6 * * 0,6 /etc/ppp/mailstart
 
mailstart is a script that i put in /etc/ppp with the following:
echo starting mail delivery "at `date` " >> /etc/ppp/mailstart.log
/usr/sbin/sendmail -q
 
I also configure sendmail to queue the mail that is going out so that it can only be forwarded at the times set in the mailstart script.
 
Please help me to find out 
1.) How to check which programme brings up the interface
2.) How to control the dialing
 
I use the ppp-on and redialer in /etc/ppp script as well as pppd for dialing
 
 


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