[Asterisk-Users] How to make asterisk send email notification of voicemessages?

[Michael Loftis]

app_voicemail.c/VoiceMail invokes the sendmail command internally to send 
email.  You must have postfix, sendmail or exim, or some other MTA that 
provides a sendmail compatibility binary.  See voicemail.conf for the 
setting that tells it where to look for the binary.

Right now app_voicemail.c does not connect directly via SMTP itself. 
Sending mail has nothing to do with POP3.  The system merely invokes 
sendmail, passes in the message it wants to send to the address specified 
in the mailbox configuration and that's it.