diff --git a/src/mailboxdb.js b/src/mailboxdb.js
index 21bc87ee0..f236eb916 100644
--- a/src/mailboxdb.js
+++ b/src/mailboxdb.js
@@ -84,7 +84,7 @@ function getMailbox(name, callback) {
     assert.strictEqual(typeof name, 'string');
     assert.strictEqual(typeof callback, 'function');
 
-    database.query('SELECT ' + MAILBOX_FIELDS + ' FROM mailboxes WHERE name = ? AND (ownerType = ? OR ownerType = ?)', [ name, exports.TYPE_APP, exports.TYPE_USER ], function (error, results) {
+    database.query('SELECT ' + MAILBOX_FIELDS + ' FROM mailboxes WHERE name = ? AND (ownerType = ? OR ownerType = ?) AND aliasTarget IS NULL', [ name, exports.TYPE_APP, exports.TYPE_USER ], function (error, results) {
         if (error) return callback(new DatabaseError(DatabaseError.INTERNAL_ERROR, error));
         if (results.length === 0) return callback(new DatabaseError(DatabaseError.NOT_FOUND));
 
@@ -95,7 +95,7 @@ function getMailbox(name, callback) {
 function listMailboxes(callback) {
     assert.strictEqual(typeof callback, 'function');
 
-    database.query('SELECT ' + MAILBOX_FIELDS + ' FROM mailboxes WHERE ownerType = ? OR ownerType = ? ORDER BY name', [ exports.TYPE_APP, exports.TYPE_USER ], function (error, results) {
+    database.query('SELECT ' + MAILBOX_FIELDS + ' FROM mailboxes WHERE (ownerType = ? OR ownerType = ?) AND aliasTarget IS NULL ORDER BY name', [ exports.TYPE_APP, exports.TYPE_USER ], function (error, results) {
         if (error) return callback(new DatabaseError(DatabaseError.INTERNAL_ERROR, error));
 
         callback(null, results);
@@ -112,7 +112,7 @@ function getGroup(name, callback) {
     //    INNER JOIN users ON groupMembers.userId = users.id
     //    WHERE mailboxes.name = <name>
 
-    database.query('SELECT ' + MAILBOX_FIELDS + ' FROM mailboxes WHERE name = ? AND ownerType = ?', [ name, exports.TYPE_GROUP ], function (error, results) {
+    database.query('SELECT ' + MAILBOX_FIELDS + ' FROM mailboxes WHERE name = ? AND ownerType = ? AND aliasTarget IS NULL', [ name, exports.TYPE_GROUP ], function (error, results) {
         if (error) return callback(new DatabaseError(DatabaseError.INTERNAL_ERROR, error));
         if (results.length === 0) return callback(new DatabaseError(DatabaseError.NOT_FOUND));
 
diff --git a/src/test/ldap-test.js b/src/test/ldap-test.js
index 33c14954d..7efb97adb 100644
--- a/src/test/ldap-test.js
+++ b/src/test/ldap-test.js
@@ -29,6 +29,8 @@ var USER_0 = {
     displayName: 'User 0'
 };
 
+var USER_0_ALIAS = 'Asterix';
+
 // normal user
 var USER_1 = {
     username: 'Username1',
@@ -98,7 +100,7 @@ function setup(done) {
         },
         function (callback) {
             async.series([
-                user.setAliases.bind(null, USER_0.id, [ 'Asterix', 'obelix' ]),
+                user.setAliases.bind(null, USER_0.id, [ USER_0_ALIAS, 'obelix' ]),
                 groups.create.bind(null, GROUP_ID),
                 groups.addMember.bind(null, GROUP_ID, USER_0.id),
                 groups.addMember.bind(null, GROUP_ID, USER_1.id)
@@ -533,6 +535,13 @@ describe('Ldap', function () {
             });
         });
 
+        it('cannot get alias as a mailbox', function (done) {
+            ldapSearch('cn=' + USER_0_ALIAS + ',ou=mailboxes,dc=cloudron', 'objectclass=mailbox', function (error, entries) {
+                expect(error).to.be.a(ldap.NoSuchObjectError);
+                done();
+            });
+        });
+
         it('non-existent mailbox', function (done) {
             ldapSearch('cn=random,ou=mailboxes,dc=cloudron', 'objectclass=mailbox', function (error) {
                 expect(error).to.be.a(ldap.NoSuchObjectError);
@@ -543,7 +552,7 @@ describe('Ldap', function () {
 
     describe('search aliases', function () {
         it('get specific alias', function (done) {
-            ldapSearch('cn=asterix,ou=mailaliases,dc=cloudron', 'objectclass=nismailalias', function (error, entries) {
+            ldapSearch('cn=' + USER_0_ALIAS + ',ou=mailaliases,dc=cloudron', 'objectclass=nismailalias', function (error, entries) {
                 if (error) return done(error);
                 expect(entries.length).to.equal(1);
                 expect(entries[0].cn).to.equal('asterix');
@@ -552,6 +561,13 @@ describe('Ldap', function () {
             });
         });
 
+        it('cannot get mailbox as alias', function (done) {
+            ldapSearch('cn=' + USER_0.username + ',ou=mailaliases,dc=cloudron', 'objectclass=nismailalias', function (error, entries) {
+                expect(error).to.be.a(ldap.NoSuchObjectError);
+                done();
+            });
+        });
+
         it('non-existent alias', function (done) {
             ldapSearch('cn=random,ou=mailaliases,dc=cloudron', 'objectclass=mailbox', function (error) {
                 expect(error).to.be.a(ldap.NoSuchObjectError);
@@ -562,7 +578,7 @@ describe('Ldap', function () {
 
     describe('search groups', function () {
         it('get specific alias', function (done) {
-            ldapSearch('cn=asterix,ou=mailaliases,dc=cloudron', 'objectclass=nismailalias', function (error, entries) {
+            ldapSearch('cn=' + USER_0_ALIAS + ',ou=mailaliases,dc=cloudron', 'objectclass=nismailalias', function (error, entries) {
                 if (error) return done(error);
                 expect(entries.length).to.equal(1);
                 expect(entries[0].cn).to.equal('asterix');