Timo wrote:

So Postfix delivers bounces to everyone by calling Dovecot LDA separately for each bounce? Looks like a Postfix configuration problem to me.

I should have been more specific... because we'd also changed domain names at the time we moved over to using Dovecot as the LDA, I temporarily disabled automatically bouncing mail addressed to invalid users because I figured that we'd have at least one who decided that they didn't want the standard formation of email addresses... What I'd wanted to happen was for Postfix to accept the message(s) and then for them to be delivered to the postmaster address so that I could address the issue.

I'm still unsure as to why, when Dovecot couldn't find the user in the tables, it copied the message to every user of the system - that seems like odd behavior, which indicates that even though the system is "working", I need to fine-tune something.

And at Charles request, here's the output of dovecot -n:

# 1.0.10: /etc/dovecot/dovecot.conf base_dir: /var/run/dovecot/ log_path: /var/log/dovecot info_log_path: /var/log.dovecot.info protocols: imap imaps pop3 pop3s disable_plaintext_auth: no login_dir: /var/run/dovecot/login login_executable(default): /usr/lib/dovecot/imap-login login_executable(imap): /usr/lib/dovecot/imap-login login_executable(pop3): /usr/lib/dovecot/pop3-login login_greeting: Dovecot ready login_process_per_connection: no valid_chroot_dirs: /var/spool/mail max_mail_processes: 2048 mail_location: maildir:/home/vmail/%d/%n mail_executable(default): /usr/lib/dovecot/imap mail_executable(imap): /usr/lib/dovecot/imap mail_executable(pop3): /usr/lib/dovecot/pop3 mail_process_size: 1024 mail_plugin_dir(default): /usr/lib/dovecot/modules/imap mail_plugin_dir(imap): /usr/lib/dovecot/modules/imap mail_plugin_dir(pop3): /usr/lib/dovecot/modules/pop3 imap_client_workarounds: delay-newmail outlook-idle netscape-eoh pop3_uidl_format(default): pop3_uidl_format(imap): pop3_uidl_format(pop3): %08Xu%08Xv pop3_client_workarounds: outlook-no-nuls oe-ns-eoh namespace: type: private separator: . prefix: INBOX. inbox: yes auth default_with_listener: mechanisms: plain login verbose: yes debug: yes passdb: driver: sql args: /etc/dovecot/dovecot-sql.conf userdb: driver: static args: uid=5000 gid=5000 home=/home/vmail/%d/%n allow_all_users=yes socket: type: listen client: path: /var/spool/postfix/private/auth mode: 432 user: postfix group: postfix master: path: /var/run/dovecot/auth-master mode: 384 user: vmail