http://www.iredmail.org/forum/topic2010 … tting.html

regnauld@178    273  A general note worth reiterating: to reduce backscatter pollution
regnauld@178    274  (sending of bounces to innocent sender addresses), please either:
regnauld@178    275
regnauld@178    276    * set $final_virus_destiny and $final_spam_destiny to D_DISCARD
regnauld@178    277      or to D_PASS  (_not_ to D_REJECT or D_BOUNCE),
regnauld@178    278
regnauld@178    279    or:
regnauld@178    280    * carefully configure virus and spam bounce suppression by:
regnauld@178    281      . configuring @viruses_that_fake_sender_maps correctly (the default
regnauld@178    282        is fine, it suppresses all bounces to infected mail), then one may
regnauld@178    283        safely set $final_virus_destiny to D_BOUNCE, it is equivalent to
regnauld@178    284        D_DISCARD for all infected mail containing malware matching the
regnauld@178    285        @viruses_that_fake_sender_maps;
regnauld@178    286
regnauld@178    287      . and: configuring @spam_dsn_cutoff_level_maps and
regnauld@178    288        @spam_dsn_cutoff_level_bysender_maps, keeping levels just slightly
regnauld@178    289        over a kill level, have a well maintained SpamAssassin with
regnauld@178    290        network tests enabled and updated rules - then one may set
regnauld@178    291        $final_spam_destiny to D_BOUNCE, which will produce bounces for
regnauld@178    292        mail with spam score between kill level and cutoff level, and
regnauld@178    293        suppress bounces above suppress level; some domains may still
regnauld@178    294        consider such practice abusive, so consider decisions twice;
regnauld@178    295
regnauld@178    296      . to monitor bounces generated by amavisd, one may assign some
regnauld@178    297        dedicated monitoring e-mail address to $dsn_bcc, which will then
regnauld@178    298        receive a copy of all delivery status notifications sent out
regnauld@178    299        by amavisd;

之前的SQL语句：
UPDATE mailbox SET lastloginipv4="INET_ATON('127.0.0.1')", lastlogindate="NOW()", lastloginprotocol="imap" WHERE username='username@example.com.cn'
修改后的SQL语句：
DATE mailbox SET lastloginipv4=INET_ATON('127.0.0.1'), lastlogindate=NOW(), lastloginprotocol="imap" WHERE username='username@example.com.cn'

echo "$(date +%Y.%m.%d-%H:%M:%S), $USER, $IP, ${1}" >> /tmp/tracking.log 2>&1

# ------------------------------------------------------------------
# Update to MySQL database.
# Note: ${MYSQL_USER} must have SELECT and UPDATE privileges.
# ------------------------------------------------------------------
MYSQL_USER='sa'
PASSWD='sa-password'
VMAIL_DB_NAME='vmail'
#
if [ X"${USER}" != X"dump-capability" ]; then
   mysql -u${MYSQL_USER} -p${PASSWD} ${VMAIL_DB_NAME} >/dev/null 2>&1 <<EOF
       UPDATE mailbox SET \
       lastloginipv4="INET_ATON('$IP')", \
       lastlogindate="NOW()", \
       lastloginprotocol="${1}" \
       WHERE username='$USER';
EOF
fi

# IMAP configuration
protocol imap {
    mail_drop_priv_before_exec=yes
    mail_executable = /usr/bin/trackLastLogin.sh imap

    mail_plugins = quota imap_quota autocreate

    imap_client_workarounds = tb-extra-mailbox-sep

    # number of connections per-user per-IP
    #mail_max_userip_connections = 10
}

# POP3 configuration
protocol pop3 {
    mail_drop_priv_before_exec=yes
    mail_executable = /usr/bin/trackLastLogin.sh imap

    mail_plugins = quota
    pop3_uidl_format = %08Xu%08Xv
    pop3_client_workarounds = outlook-no-nuls oe-ns-eoh

    # number of connections per-user per-IP
    #mail_max_userip_connections = 10
}

mysql> select lastlogindate,lastloginipv4,lastloginprotocol from mailbox;
+---------------------+---------------+-------------------+
| lastlogindate       | lastloginipv4 | lastloginprotocol |
+---------------------+---------------+-------------------+
| 0000-00-00 00:00:00 |             0 |                   |
| 0000-00-00 00:00:00 |             0 | imap              |
| 0000-00-00 00:00:00 |             0 |                   |
+---------------------+---------------+-------------------+
3 rows in set (0.00 sec)