I've just taken over support for an OS X Server (v10.6.8) box, and am a bit new at Postfix & Dovecot.

We're having an problem where, intermittently, dovecot seems to be bouncing messages inbound for some of my existing users.

Here is the mail.log entry for a successful delivery:

Aug 21 16:58:45 mail postfix/pipe[64094]: D68783AE0F75: to=sblondin@eem.ca, relay=dovecot, delay=0.08, delays=0/0.01/0/0.07, dsn=2.0.0, status=sent (delivered via dovecot service)

And here is what a bounce looks like

Aug 22 07:29:28 mail postfix/local[93916]: error: od[getpwnam_ext]: No record for user sblondin Aug 22 07:29:28 mail postfix/pipe[93944]: 852C43AE7ACC: to=sblondin@eem.ca, relay=dovecot, delay=15, delays=0.14/0.05/0/15, dsn=5.1.1, status=bounced (user unknown)

And a bit later another succcessful delivery.

Aug 22 07:56:37 mail postfix/pipe[95021]: 14AF73AE82F0: to=sblondin@eem.ca, relay=dovecot, delay=0.5, delays=0.08/0.02/0/0.4, dsn=2.0.0, status=sent (delivered via dovecot service)

No changes to this user's account were made during this time period. I'm flummoxed.

Anythoughts as to what might be going on here, and/or how to debug this further?

Thanks in advance...

Ian

/usr/sbin/dovecotd --version 1.1.20apple0.5

sh-3.2# /usr/sbin/dovecotd -n # 1.1.20apple0.5: /private/etc/dovecot/dovecot.conf Warning: fd limit 256 is lower than what Dovecot can use under full load (more than 456). Either grow the limit or change login_max_processes_count and max_mail_processes settings # OS: Darwin 10.8.0 x86_64 hfs base_dir: /var/run/dovecot syslog_facility: local6 protocols: managesieve imaps imap listen(default): * listen(imap): * listen(managesieve): *:2000 ssl_ca_file: /etc/certificates/mail.eem.ca.98CEBC1921A5C908068A7CB64F0364C1D5DEF795.chain.pem ssl_cert_file: /etc/certificates/mail.eem.ca.98CEBC1921A5C908068A7CB64F0364C1D5DEF795.cert.pem ssl_key_file: /etc/certificates/mail.eem.ca.98CEBC1921A5C908068A7CB64F0364C1D5DEF795.key.pem ssl_cipher_list: ALL:!LOW:!SSLv2:!aNULL:!ADH:!eNULL disable_plaintext_auth: no login_dir: /var/run/dovecot/login login_executable(default): /usr/libexec/dovecot/imap-login login_executable(imap): /usr/libexec/dovecot/imap-login login_executable(managesieve): /usr/libexec/dovecot/managesieve-login login_user: _dovecot login_process_per_connection: no max_mail_processes: 200 mail_max_userip_connections(default): 20 mail_max_userip_connections(imap): 20 mail_max_userip_connections(managesieve): 10 verbose_proctitle: yes first_valid_uid: 6 first_valid_gid: 6 mail_access_groups: mail mail_location: maildir:/var/spool/imap/dovecot/mail/%u mail_executable(default): /usr/libexec/dovecot/imap mail_executable(imap): /usr/libexec/dovecot/imap mail_executable(managesieve): /usr/libexec/dovecot/managesieve mail_process_sharing(default): full mail_process_sharing(imap): full mail_process_sharing(managesieve): none mail_max_connections(default): 5 mail_max_connections(imap): 5 mail_max_connections(managesieve): 20 mail_plugins(default): quota imap_quota mail_plugins(imap): quota imap_quota mail_plugins(managesieve): mail_plugin_dir(default): /usr/lib/dovecot/imap mail_plugin_dir(imap): /usr/lib/dovecot/imap mail_plugin_dir(managesieve): /usr/lib/dovecot/managesieve sieve_storage(default): sieve_storage(imap): sieve_storage(managesieve): /var/spool/imap/dovecot/sieve-scripts/%u sieve(default): sieve(imap): sieve(managesieve): /var/spool/imap/dovecot/sieve-scripts/%u/dovecot.sieve lda: postmaster_address: postmaster@example.com hostname: mail.eem.ca mail_plugins: push_notify cmusieve quota quota_full_tempfail: yes sendmail_path: /usr/sbin/sendmail auth_socket_path: /var/run/dovecot/auth-master log_path: /var/log/mailaccess.log info_log_path: /var/log/mailaccess.log auth default: mechanisms: plain login gssapi cram-md5 verbose: yes passdb: driver: od userdb: driver: od args: partition=/etc/dovecot/partition_map.conf enforce_quotas=no socket: type: listen master: path: /var/run/dovecot/auth-master mode: 384 user: _dovecot group: mail plugin: quota_warning: storage=100%% /usr/libexec/dovecot/quota-exceeded.sh quota: maildir:User quota sieve: /var/spool/imap/dovecot/sieve-scripts/%u/dovecot.sieve