sendmail and exim4

[Valdir Marcos]

init---atd
     +-bash
     +-cron---firebird
     ¦      +-sendmail
     +-cron---cron---sendmail
     ¦             +-sh---curl
     +-dhclient
     +-exim4


How can I discover what sendmail and exim4 are doing in my Debian Sarge?
Tho whom they send messages in a server that, theoricaly, neither have POP nor 
SMTP working?

Thanks,

Valdir