diff --git a/neutron_lib/api/definitions/constants.py b/neutron_lib/api/definitions/constants.py
index 6e97f08..3747718 100644
--- a/neutron_lib/api/definitions/constants.py
+++ b/neutron_lib/api/definitions/constants.py
@@ -12,6 +12,8 @@
 #    under the License.
 
 # neutron-fwaas constants
+from neutron_lib import constants
+
 FIREWALL_GROUPS = 'firewall_groups'
 FIREWALL_POLICIES = 'firewall_policies'
 FIREWALL_RULES = 'firewall_rules'
@@ -21,3 +23,7 @@ FWAAS_ALLOW = "allow"
 FWAAS_DENY = "deny"
 FWAAS_REJECT = "reject"
 FW_VALID_ACTION_VALUES = [FWAAS_ALLOW, FWAAS_DENY, FWAAS_REJECT]
+
+# Firewall Protocol List
+
+FW_PROTOCOL_VALUES = list(constants.IPTABLES_PROTOCOL_MAP.keys()) + [None]
diff --git a/neutron_lib/api/definitions/firewall.py b/neutron_lib/api/definitions/firewall.py
index a232d35..b8ce2da 100644
--- a/neutron_lib/api/definitions/firewall.py
+++ b/neutron_lib/api/definitions/firewall.py
@@ -12,7 +12,6 @@
 
 from neutron_lib.api import converters
 from neutron_lib.api.definitions import constants as api_const
-from neutron_lib import constants
 from neutron_lib.db import constants as db_const
 
 # The alias of the extension.
@@ -65,11 +64,11 @@ RESOURCE_ATTRIBUTE_MAP = {
                    'convert_to': converters.convert_to_boolean,
                    'is_visible': True, 'required_by_policy': True,
                    'enforce_policy': True},
-        'protocol': {'allow_post': True, 'allow_put': True,
-                     'is_visible': True, 'default': None,
-                     'convert_to': converters.convert_to_protocol,
-                     'validate': {'type:values':
-                                  constants.IPTABLES_PROTOCOL_MAP}},
+        'protocol': {
+            'allow_post': True, 'allow_put': True,
+            'is_visible': True, 'default': None,
+            'convert_to': converters.convert_to_protocol,
+            'validate': {'type:values': api_const.FW_PROTOCOL_VALUES}},
         'ip_version': {'allow_post': True, 'allow_put': True,
                        'default': 4, 'convert_to': converters.convert_to_int,
                        'validate': {'type:values': [4, 6]},
diff --git a/neutron_lib/api/definitions/firewall_v2.py b/neutron_lib/api/definitions/firewall_v2.py
index 40634cb..60ed405 100644
--- a/neutron_lib/api/definitions/firewall_v2.py
+++ b/neutron_lib/api/definitions/firewall_v2.py
@@ -12,7 +12,6 @@
 
 from neutron_lib.api import converters
 from neutron_lib.api.definitions import constants as api_const
-from neutron_lib import constants
 from neutron_lib.db import constants as db_const
 
 # The alias of the extension.
@@ -66,11 +65,11 @@ RESOURCE_ATTRIBUTE_MAP = {
                    'default': False, 'is_visible': True,
                    'convert_to': converters.convert_to_boolean,
                    'required_by_policy': True, 'enforce_policy': True},
-        'protocol': {'allow_post': True, 'allow_put': True,
-                     'is_visible': True, 'default': None,
-                     'convert_to': converters.convert_to_protocol,
-                     'validate': {'type:values':
-                                  constants.IPTABLES_PROTOCOL_MAP}},
+        'protocol': {
+            'allow_post': True, 'allow_put': True,
+            'is_visible': True, 'default': None,
+            'convert_to': converters.convert_to_protocol,
+            'validate': {'type:values': api_const.FW_PROTOCOL_VALUES}},
         'ip_version': {'allow_post': True, 'allow_put': True,
                        'default': 4, 'convert_to': converters.convert_to_int,
                        'validate': {'type:values': [4, 6]},