diff -Naur a/libs/ldaplib/conn_utils.py b/libs/ldaplib/conn_utils.py
--- a/libs/ldaplib/conn_utils.py    2016-05-10 08:26:17.000000000 +0800
+++ b/libs/ldaplib/conn_utils.py    2016-07-20 11:58:42.000000000 +0800
@@ -1,6 +1,7 @@
 # Author: Zhang Huangbin <zhb _at_ iredmail.org>

 from libs.logger import logger
+from libs import utils
 import ldap
 import settings
 from libs import MAILLIST_POLICY_MEMBERSONLY, \
@@ -63,6 +64,10 @@
     basedn = domaindn
     search_scope = 2

+    # Use 'moderatorsonly' instead of 'allowedonly'
+    if policy == 'allowedonly':
+        policy = 'moderatorsonly'
+
     # Set search filter, attributes based on policy.
     # Override base dn, scope if necessary.
     if policy == MAILLIST_POLICY_MEMBERSONLY:
@@ -73,7 +78,7 @@
                         ')'

         # Get both mail and shadowAddress.
-        search_attrs = ['mail', 'shadowAddress', ]
+        search_attrs = ['mail', 'shadowAddress']
     elif policy == MAILLIST_POLICY_MEMBERSANDMODERATORSONLY:
         # Policy: policy==
         # Filter used to get both members and moderators.
@@ -186,3 +191,27 @@
                         allowed_senders += ['.' + d for d in domains]

     return [u.lower() for u in allowed_senders]
+
+
+def is_local_domain(conn, domain):
+    if not utils.is_domain(domain):
+        return False
+
+    if utils.is_server_hostname(domain):
+        return True
+
+    try:
+        filter_domains = '(&(objectClass=mailDomain)'
+        filter_domains += '(|(domainName=%s)(domainAliasName=%s))' % (domain, domain)
+        filter_domains += ')'
+
+        qr = conn.search_s(settings.ldap_basedn,
+                           1,   # 1 == ldap.SCOPE_ONELEVEL
+                           filter_domains,
+                           ['dn'])
+        if qr:
+            return True
+    except Exception, e:
+        logger.error('<!> Error while querying alias domain: %s' % str(e))
+
+    return False
diff -Naur a/libs/sql/__init__.py b/libs/sql/__init__.py
--- a/libs/sql/__init__.py  2016-05-10 08:26:17.000000000 +0800
+++ b/libs/sql/__init__.py  2016-07-20 11:58:48.000000000 +0800
@@ -0,0 +1,27 @@
+from libs.logger import logger
+from libs import utils
+
+def is_local_domain(conn, domain):
+    if not utils.is_domain(domain):
+        return False
+
+    if utils.is_server_hostname(domain):
+        return True
+
+    try:
+        sql = """SELECT alias_domain
+                   FROM alias_domain
+                  WHERE alias_domain='%s' OR target_domain='%s'
+                  LIMIT 1""" % (domain, domain)
+        logger.debug('[SQL] query alias domains: \n%s' % sql)
+
+        qr = conn.execute(sql)
+        sql_record = qr.fetchone()
+        logger.debug('SQL query result: %s' % str(sql_record))
+
+        if sql_record:
+            return True
+    except Exception, e:
+        logger.error('<!> Error while querying alias domain: %s' % str(e))
+
+    return False
diff -Naur a/plugins/amavisd_wblist.py b/plugins/amavisd_wblist.py
--- a/plugins/amavisd_wblist.py 2016-05-10 08:26:17.000000000 +0800
+++ b/plugins/amavisd_wblist.py 2016-07-20 11:58:10.000000000 +0800
@@ -50,6 +50,11 @@

 REQUIRE_AMAVISD_DB = True

+if settings.backend == 'ldap':
+    from libs.ldaplib.conn_utils import is_local_domain
+else:
+    from libs.sql import is_local_domain
+

 def query_external_addresses(conn, addresses):
     '''Return list of `mailaddr.id` of external addresses.'''
@@ -179,6 +184,7 @@

 def restriction(**kwargs):
     conn = kwargs['conn_amavisd']
+    conn_vmail = kwargs['conn_vmail']

     if not conn:
         logger.error('Error, no valid Amavisd database connection.')
@@ -186,9 +192,11 @@

     # Get sender
     sender = kwargs['sender']
+    sender_domain = kwargs['sender_domain']
     if kwargs['sasl_username']:
         # Use sasl_username as sender for outgoing email
         sender = kwargs['sasl_username']
+        sender_domain = kwargs['sasl_username_domain']

     if not sender:
         logger.debug('Bypass: both sender and sasl_username are empty.')
@@ -221,7 +229,7 @@
     logger.debug('Possible policy senders: %s' % str(valid_senders))
     logger.debug('Possible policy recipients: %s' % str(valid_recipients))

-    if kwargs['sasl_username']:
+    if kwargs['sasl_username'] or is_local_domain(conn=conn_vmail, domain=sender_domain):
         logger.debug('Apply wblist for outbound message.')

         id_of_ext_addresses = []
--- a/libs/utils.py 2016-05-10 08:26:17.000000000 +0800
+++ b/libs/utils.py 2016-07-20 12:05:44.000000000 +0800
@@ -1,5 +1,6 @@
 import re
 import time
+import socket

 from sqlalchemy import create_engine

@@ -355,3 +356,12 @@
             return _user + '@' + _domain

     return mail
+
+
+def is_server_hostname(domain):
+    name = socket.gethostname()
+
+    if domain == name:
+        return True
+    else:
+        return False