[Dovecot] Why is dovecot involved in my smtp process

[SM]

Hi Steve,
At 07:16 23-02-2012, Steve Campbell wrote:
>I've been trying to get smtp auth set up for days. All my sendmail 
>and sasl2 stuff seems to be proper, but the user can't use the 
>system on port 587, which is where I require authorization.
>
>Now I see where messages are in my maillog of the type:
>
>auth: pam_unix(dovecot:auth) : authentication failure ........
>
>Why is dovecot involved in my smtp processes and how do I fix this. 
>I've got some very

If you are using sendmail as the MTA, Dovecot is not involved for 
authentication on mail submission.  The maillog line you provided 
does not contain enough information to tell what triggered the error.

Regards,
-sm