diff --git a/ec2_rule_transformer.py b/ec2_rule_transformer.py
index a83c63c..5f32a3a 100644
--- a/ec2_rule_transformer.py
+++ b/ec2_rule_transformer.py
@@ -8,8 +8,10 @@ class EC2RuleTransformer:
         self.ec2_connection = ec2_connection
 
     def to_rule(self, ec2_rule):
-        rule_args = deepcopy(vars(ec2_rule))
-        self._delete_unused_rule_args(rule_args)
+        rule_args = {}
+        rule_args['ip_protocol'] = ec2_rule.ip_protocol
+        rule_args['from_port'] = ec2_rule.from_port
+        rule_args['to_port'] = ec2_rule.to_port
 
         if ec2_rule.grants[0].cidr_ip:
             rule_args['ip_range'] = ec2_rule.grants[0].cidr_ip
@@ -17,11 +19,4 @@ class EC2RuleTransformer:
             group_id = ec2_rule.grants[0].group_id
             rule_args['group_name'] = self.ec2_connection.get_all_security_groups(group_ids=group_id)[0].name
 
-        return Rule(**rule_args)
-
-    def _delete_unused_rule_args(self, rule_args):
-        del rule_args['grants']
-        del rule_args['parent']
-        del rule_args['item']
-        del rule_args['ipRanges']
-        del rule_args['groups']
\ No newline at end of file
+        return Rule(**rule_args)
\ No newline at end of file
diff --git a/openstack_rule_transformer.py b/openstack_rule_transformer.py
index 5a84cb9..300198a 100644
--- a/openstack_rule_transformer.py
+++ b/openstack_rule_transformer.py
@@ -3,11 +3,11 @@ from rule import Rule
 
 
 class OpenstackRuleTransformer:
-
     def to_rule(self, openstack_rule):
-        rule_args = deepcopy(openstack_rule)
-
-        self._delete_unused_rule_args(rule_args)
+        rule_args = {}
+        rule_args['ip_protocol'] = openstack_rule['ip_protocol']
+        rule_args['from_port'] = str(openstack_rule['from_port'])
+        rule_args['to_port'] = str(openstack_rule['to_port'])
 
         if 'cidr' in openstack_rule['ip_range']:
             rule_args['ip_range'] = openstack_rule['ip_range']['cidr']
@@ -15,8 +15,3 @@ class OpenstackRuleTransformer:
             rule_args['group_name'] = openstack_rule['group']['name']
 
         return Rule(**rule_args)
-
-    def _delete_unused_rule_args(self, rule_args):
-        del rule_args['group']
-        del rule_args['parent_group_id']
-        del rule_args['id']
\ No newline at end of file
diff --git a/tests/unit/test_openstack_rule_transformer.py b/tests/unit/test_openstack_rule_transformer.py
index 887a3b2..b86466c 100644
--- a/tests/unit/test_openstack_rule_transformer.py
+++ b/tests/unit/test_openstack_rule_transformer.py
@@ -8,7 +8,7 @@ class TestOpenstackRuleTransformer(unittest.TestCase):
     def setUp(self):
         self.openstack_rule_transformer = OpenstackRuleTransformer()
 
-    def test_should_copy_to_port(self):
+    def test_should_copy_to_port_as_string(self):
         openstack_rule = {
             'ip_protocol': 'abc',
             'from_port': 123,
@@ -19,4 +19,17 @@ class TestOpenstackRuleTransformer(unittest.TestCase):
             'id': 18
         }
         rule = self.openstack_rule_transformer.to_rule(openstack_rule)
-        self.assertEqual(rule.to_port, openstack_rule['to_port'])
\ No newline at end of file
+        self.assertEqual(rule.to_port, str(openstack_rule['to_port']))
+
+    def test_should_copy_from_port_as_string(self):
+        openstack_rule = {
+            'ip_protocol': 'abc',
+            'from_port': 123,
+            'to_port': 456,
+            'group': {},
+            'parent_group_id': 55,
+            'ip_range': {'cidr': '9.8.7.6/55'},
+            'id': 18
+        }
+        rule = self.openstack_rule_transformer.to_rule(openstack_rule)
+        self.assertEqual(rule.from_port, str(openstack_rule['from_port']))
\ No newline at end of file