[Dovecot] Logging "issue" with PAM authentication

[Steve Johnson]

Hi,

We currently have a postfix/dovecot setup using nss_ldap with PAM for
authentication. Everything is working fine, but there are excessive
"error" messages in /var/log/messages that I'd like to prevent from
happening.

Since auth_userdb defaults to passwd and that our users are not in the
passwd file, we get the following message everytime a user logs in:

Jul  7 13:34:37 hostname dovecot(pam_unix)[32206]: check pass; user
unknown
Jul  7 13:34:37 hostname dovecot(pam_unix)[32206]: authentication
failure; logname= uid=0 euid=0 tty= ruser= rhost=

We of course also get the input that a user has logged in, in
/var/log/maillog:

imap-login: Jul 07 13:34:37 Info: Login: username [xxx.xxx.xxx.xxx]

I've tried changing auth_verbose to no, and I still get those messages.
Is there any way to prevent this from happening?

Thanks a lot,
Steve Johnson