Knowledge Base

When mailbox on Plesk server is full, email sent to the mailbox is rejected during SMTP secession without bounce message

Symptoms

When mailbox on Plesk server is full, email sent to the mailbox is rejected during SMTP session without bounce message.
In /var/log/maillog, the following entries can be found:
qmail-queue-handlers[15273]: Handlers Filter before-queue for qmail started ...
qmail-queue-handlers[15273]: [email protected]
qmail-queue-handlers[15273]: [email protected]
qmail-queue-handlers[15273]: handlers_stderr: DATA Mailbox full#015
qmail-queue-handlers[15273]: handlers_stderr: DEFER
qmail-queue-handlers[15273]: DEFER during call 'check-quota' handler

Cause

By default, Plesk's mail service does not send bounce response when a user's mailbox is full to prevent mass spamming with bounce messages. Plesk "check-quota" mail handler is used for deferring incoming emails without bounce message.

Resolution

The feature described above can be disabled on Plesk server.

Solution for Plesk Onyx and higher

Note: Disabling "check-quota" mail handler is strongly not recommended because server's IP may be blacklisted due to lot of bounce messages which can be considered as spam by other servers.

Note: if user runs "plesk repair mail" command line tool it will re-enable "check-quota" mail handler back.

Connect to the server via SSH.
Run the following commands to disable "check-quota" handler:

/usr/local/psa/admin/sbin/mail_handlers_control --disable --name=check-quota --type=global --queue=before-queue
/usr/local/psa/admin/sbin/mail_handlers_control --disable --name=check-quota --type=global --queue=before-sendmail

After disabling 'check-quota' handler bounce messages will be send each time when recipient's mailbox has no sufficient space to receive an email.

Solution for Plesk 12.0

Note: Disabling "check-quota" mail handler is strongly not recommended because server's IP may be blacklisted due to lot of bounce messages which can be considered as spam by other servers.

Connect to the server via SSH.
Backup Plesk database:

plesk db dump psa > /root/psa_dump.`date +%F.%s`.sql
Run the following commands to disable "check-quota" handler:

# MYSQL_PWD=`cat /etc/psa/.psa.shadow` mysql -u admin psa -e "REPLACE INTO misc VALUES ('reject_mail_when_overquota', 'false')"

For 64-bit OS run the command:

# /usr/lib64/plesk-9.0/mail_mailbox_restore --handlers-only

For 32-bit OS run the command:

# /usr/lib/plesk-9.0/mail_mailbox_restore --handlers-only