diff --git a/Lib/ldap/filter.py b/Lib/ldap/filter.py
index 782737aa..e95b5559 100644
--- a/Lib/ldap/filter.py
+++ b/Lib/ldap/filter.py
@@ -87,3 +87,21 @@ def time_span_filter(
         until_timestr=strf_secs(until_timestamp),
     )
     # end of time_span_filter()
+
+
+def is_filter(ldap_filter):
+    """
+    Returns True if `ldap_filter' can be parsed as a valid LDAP filter, otherwise False is returned.
+    """
+    import ldap
+    lo = ldap.initialize('')
+    try:
+        lo.search_ext_s('', ldap.SCOPE_BASE, ldap_filter)
+    except (ldap.FILTER_ERROR, TypeError, ValueError):
+        return False
+    except ldap.SERVER_DOWN:
+        # the filter syntax is valid, as the connection is not bound we expect SERVER_DOWN here
+        return True
+    finally:
+        lo.unbind()
+    raise RuntimeError('Could not check filter syntax.')  # can not happen
diff --git a/Tests/t_ldap_filter.py b/Tests/t_ldap_filter.py
index 313b3733..972d9bf0 100644
--- a/Tests/t_ldap_filter.py
+++ b/Tests/t_ldap_filter.py
@@ -10,7 +10,7 @@
 # Switch off processing .ldaprc or ldap.conf before importing _ldap
 os.environ['LDAPNOINIT'] = '1'
 
-from ldap.filter import escape_filter_chars
+from ldap.filter import escape_filter_chars, is_filter, filter_format
 
 
 class TestDN(unittest.TestCase):
@@ -18,6 +18,27 @@ class TestDN(unittest.TestCase):
     test ldap.functions
     """
 
+    def test_is_filter(self):
+        """
+        test function is_filter()
+        """
+        self.assertEqual(is_filter(''), True)
+        self.assertEqual(is_filter('foo='), True)
+        self.assertEqual(is_filter('foo=bar'), True)
+        self.assertEqual(is_filter('foo=*'), True)
+        self.assertEqual(is_filter(filter_format('foo=%s', ['*'])), True)
+        self.assertEqual(is_filter('(foo=bar)'), True)
+        self.assertEqual(is_filter('(&(foo=bar))'), True)
+        self.assertEqual(is_filter('(|(foo=bar))'), True)
+        self.assertEqual(is_filter('foo>='), True)
+        self.assertEqual(is_filter('(foo>=)'), True)
+        self.assertEqual(is_filter('foo==bar'), True)
+        self.assertEqual(is_filter('foobar'), False)
+        self.assertEqual(is_filter('(foo='), False)
+        self.assertEqual(is_filter('foo=)'), False)
+        self.assertEqual(is_filter('=bar'), False)
+        self.assertEqual(is_filter('foo=\x00'), False)
+
     def test_escape_filter_chars_mode0(self):
         """
         test function escape_filter_chars() with escape_mode=0