diff --git a/vlanmang.py b/vlanmang.py
index 92f3b36..52b286b 100644
--- a/vlanmang.py
+++ b/vlanmang.py
@@ -67,7 +67,7 @@ class SwitchConfig(object):
 			res.update(self._vlanconf[id].get('t', []))
 
 		# add in the ignore ports
-		res.update(self._ignports)
+		res.update(self.ignports)
 
 		# filter out the strings
 		strports = set(x for x in res if isinstance(x, str))
@@ -95,12 +95,21 @@ def _intstobits(*ints):
 	return ''.join(r)
 
 def _cmpbits(a, b):
-	last1a = a.rindex('1')
-	last1b = b.rindex('1')
+	try:
+		last1a = a.rindex('1')
+	except ValueError:
+		last1a = -1
+		a = ''
+	try:
+		last1b = b.rindex('1')
+	except ValueError:
+		last1b = -1
+		b = ''
+
 	if last1a != -1:
-		a = a[:last1a]
+		a = a[:last1a + 1]
 	if last1b != -1:
-		b = b[:last1b]
+		b = b[:last1b + 1]
 
 	return a == b
 
@@ -342,8 +351,13 @@ class _TestMisc(unittest.TestCase):
 		self.assertTrue(_cmpbits('111000', '111'))
 		self.assertTrue(_cmpbits('000111000', '000111'))
 		self.assertTrue(_cmpbits('11', '11'))
+		self.assertTrue(_cmpbits('0', '000'))
 		self.assertFalse(_cmpbits('0011', '11'))
 		self.assertFalse(_cmpbits('11', '0011'))
+		self.assertFalse(_cmpbits('10', '000'))
+		self.assertFalse(_cmpbits('0', '1000'))
+		self.assertFalse(_cmpbits('00010', '000'))
+		self.assertFalse(_cmpbits('0', '001000'))
 
 	def test_pvidegressuntagged(self):
 		data = {