diff --git a/letsencrypt/plugins/common.py b/letsencrypt/plugins/common.py
index 707ed7e57..a9410d514 100644
--- a/letsencrypt/plugins/common.py
+++ b/letsencrypt/plugins/common.py
@@ -118,7 +118,7 @@ class Addr(object):
             port = ''
             if len(str_addr) > endIndex + 2 and str_addr[endIndex + 1] == ':':
                 port = str_addr[endIndex + 2:]
-            return cls((host, port), True)
+            return cls((host, port), ipv6=True)
         else:
             tup = str_addr.partition(':')
             return cls((tup[0], tup[2]))
@@ -173,6 +173,9 @@ class Addr(object):
         """Explode IPv6 address for comparison"""
         result = ['0', '0', '0', '0', '0', '0', '0', '0']
         addr_list = addr.split(":")
+        if len(addr_list) > len(result):
+            # too long, truncate
+            addr_list = addr_list[0:len(result)]
         append_to_end = False
         for i in range(0, len(addr_list)):
             block = addr_list[i]
diff --git a/letsencrypt/plugins/common_test.py b/letsencrypt/plugins/common_test.py
index 9021e7e42..292248b90 100644
--- a/letsencrypt/plugins/common_test.py
+++ b/letsencrypt/plugins/common_test.py
@@ -84,6 +84,8 @@ class AddrTest(unittest.TestCase):
         self.addr4 = Addr.fromstring("[fe00::1]")
         self.addr5 = Addr.fromstring("[fe00::1]:*")
         self.addr6 = Addr.fromstring("[fe00::1]:80")
+        self.addr7 = Addr.fromstring("[fe00::1]:5")
+        self.addr8 = Addr.fromstring("[fe00:1:2:3:4:5:6:7:8:9]:8080")
 
     def test_fromstring(self):
         self.assertEqual(self.addr1.get_addr(), "192.168.1.1")
@@ -102,6 +104,9 @@ class AddrTest(unittest.TestCase):
                          "fe00:0:0:0:0:0:0:1")
         self.assertEqual(self.addr1.get_ipv6_exploded(),
                          "")
+        self.assertEqual(self.addr7.get_port(), "5")
+        self.assertEqual(self.addr7.get_ipv6_exploded(),
+                         "fe00:1:2:3:4:5:6:7")
 
     def test_str(self):
         self.assertEqual(str(self.addr1), "192.168.1.1")