diff --git a/fail2ban/server/filter.py b/fail2ban/server/filter.py
index deb47a4b..3682125c 100644
--- a/fail2ban/server/filter.py
+++ b/fail2ban/server/filter.py
@@ -375,7 +375,7 @@ class Filter(JailThread):
 	# @return True if IP address is in ignore list
 
 	def inIgnoreIPList(self, ip, log_ignore=False):
-		if isinstance(ip, basestring):
+		if not isinstance(ip, IPAddr):
 			ip = IPAddr(ip)
 		for net in self.__ignoreIpList:
 			# if it isn't a valid IP address, try DNS resolution
@@ -1037,7 +1037,10 @@ class DNSUtils:
 			return v
 		# retrieve name
 		try:
-			v = socket.gethostbyaddr(ip.ntoa())[0]
+			if not isinstance(ip, IPAddr):
+				v = socket.gethostbyaddr(ip)[0]
+			else:
+				v = socket.gethostbyaddr(ip.ntoa())[0]
 		except socket.error, e:
 			logSys.debug("Unable to find a name for the IP %s: %s", ip, e)
 			v = None
diff --git a/fail2ban/tests/filtertestcase.py b/fail2ban/tests/filtertestcase.py
index ae22b88f..b5a772d9 100644
--- a/fail2ban/tests/filtertestcase.py
+++ b/fail2ban/tests/filtertestcase.py
@@ -1314,9 +1314,9 @@ class DNSUtilsNetworkTests(unittest.TestCase):
 		res = DNSUtils.textToIp('www.example.com', 'no')
 		self.assertEqual(res, [])
 		res = DNSUtils.textToIp('www.example.com', 'warn')
-		self.assertEqual(res, ['93.184.216.34'])
+		self.assertEqual(res, ['93.184.216.34', '2606:2800:220:1:248:1893:25c8:1946'])
 		res = DNSUtils.textToIp('www.example.com', 'yes')
-		self.assertEqual(res, ['93.184.216.34'])
+		self.assertEqual(res, ['93.184.216.34', '2606:2800:220:1:248:1893:25c8:1946'])
 
 	def testTextToIp(self):
 		# Test hostnames
@@ -1328,7 +1328,7 @@ class DNSUtilsNetworkTests(unittest.TestCase):
 		for s in hostnames:
 			res = DNSUtils.textToIp(s, 'yes')
 			if s == 'www.example.com':
-				self.assertEqual(res, ['93.184.216.34'])
+				self.assertEqual(res, ['93.184.216.34', '2606:2800:220:1:248:1893:25c8:1946'])
 			else:
 				self.assertEqual(res, [])