how to stop automatic system dialing
 

hi,
when i boot mandrake 10,while loading sendmail at boot, the system
automatically start dialing the connection to connect to the internet,and
it is continuting without any interuption even the boot is completely
finished,so i have to unplug the phone line to stop hearing this dialing
tones,i don't know how to stop this,plz help me.
:(