diff --git a/configutilities/configutilities/configutilities/common/configobjects.py b/configutilities/configutilities/configutilities/common/configobjects.py
index 223cda887e..7f9a0d99f7 100755
--- a/configutilities/configutilities/configutilities/common/configobjects.py
+++ b/configutilities/configutilities/configutilities/common/configobjects.py
@@ -123,6 +123,7 @@ class Network(object):
         self.multicast_cidr = None
         self.start_address = None
         self.end_address = None
+        self.start_end_in_config = False
         self.floating_address = None
         self.address_0 = None
         self.address_1 = None
@@ -312,6 +313,7 @@ class Network(object):
                     raise ConfigFail("Address range for %s must contain at "
                                      "least %d addresses." %
                                      (network_name, min_addresses))
+                self.start_end_in_config = True
 
             if floating_address_str or address_0_str or address_1_str:
                 if not floating_address_str:
diff --git a/configutilities/configutilities/configutilities/common/validator.py b/configutilities/configutilities/configutilities/common/validator.py
index e38b44f5a1..4536b8d455 100755
--- a/configutilities/configutilities/configutilities/common/validator.py
+++ b/configutilities/configutilities/configutilities/common/validator.py
@@ -4,10 +4,10 @@ Copyright (c) 2015-2017 Wind River Systems, Inc.
 SPDX-License-Identifier: Apache-2.0
 
 """
-
 from configobjects import DEFAULT_NAMES, NETWORK_PREFIX_NAMES, OAM_TYPE, \
     MGMT_TYPE, Network, REGION_CONFIG, VALID_LINK_SPEED, INFRA_TYPE, \
     DEFAULT_DOMAIN_NAME, HP_NAMES, SUBCLOUD_CONFIG
+from netaddr import IPRange
 from utils import lag_mode_to_str, validate_network_str, \
     check_network_overlap, is_mtu_valid, is_speed_valid, get_service, \
     get_optional
@@ -382,6 +382,33 @@ class ConfigValidator(object):
                              "network" %
                              (mgmt_prefix, str(self.mgmt_network.cidr)))
 
+        if (self.system_dc_role ==
+                DISTRIBUTED_CLOUD_ROLE_SYSTEMCONTROLLER):
+            # For Distributed Cloud SystemController, we require the setting
+            # of the IP_START_ADDRESS/IP_END_ADDRESS config settings so as to
+            # raise awareness that some space in MGMT subnet must be set aside
+            # for gateways to reach subclouds.
+
+            if not self.mgmt_network.start_end_in_config:
+                raise ConfigFail("IP_START_ADDRESS and IP_END_ADDRESS required"
+                                 " for %s network as this configuration "
+                                 "requires address space left for gateway "
+                                 "address(es)" % mgmt_prefix)
+            else:
+                # Warn user that some space in the management subnet must
+                # be reserved for the system controller gateway address(es)
+                # used to communicate with the subclouds. - 2 because of
+                # subnet and broadcast addresses.
+                address_range = \
+                    IPRange(str(self.mgmt_network.start_address),
+                            str(self.mgmt_network.end_address)).size
+
+                if address_range >= (self.mgmt_network.cidr.size - 2):
+                    raise ConfigFail(
+                        "Address range for %s network too large, no addresses"
+                        " left for gateway(s), required in this "
+                        "configuration." % mgmt_prefix)
+
         if self.mgmt_network.logical_interface.lag_interface:
             supported_lag_mode = [1, 4]
             if (self.mgmt_network.logical_interface.lag_mode not in
diff --git a/controllerconfig/controllerconfig/controllerconfig/configassistant.py b/controllerconfig/controllerconfig/controllerconfig/configassistant.py
index 2bd5d27058..728afcf777 100644
--- a/controllerconfig/controllerconfig/controllerconfig/configassistant.py
+++ b/controllerconfig/controllerconfig/controllerconfig/configassistant.py
@@ -1116,22 +1116,31 @@ class ConfigAssistant():
             except ValidateFail as e:
                 print "{}".format(e)
 
-        while True:
-            user_input = raw_input(
-                "Use entire management subnet [Y/n]: ")
-            if user_input.lower() == 'q':
-                raise UserQuit
-            elif user_input.lower() == 'y':
-                self.use_entire_mgmt_subnet = True
-                break
-            elif user_input.lower() == 'n':
-                self.use_entire_mgmt_subnet = False
-                break
-            elif user_input == "":
-                break
-            else:
-                print "Invalid choice"
-                continue
+        if (self.system_dc_role !=
+                sysinv_constants.DISTRIBUTED_CLOUD_ROLE_SYSTEMCONTROLLER):
+            while True:
+                user_input = raw_input(
+                    "Use entire management subnet [Y/n]: ")
+                if user_input.lower() == 'q':
+                    raise UserQuit
+                elif user_input.lower() == 'y':
+                    self.use_entire_mgmt_subnet = True
+                    break
+                elif user_input.lower() == 'n':
+                    self.use_entire_mgmt_subnet = False
+                    break
+                elif user_input == "":
+                    break
+                else:
+                    print "Invalid choice"
+                    continue
+        else:
+            self.use_entire_mgmt_subnet = False
+            print textwrap.fill(
+                "Configured as Distributed Cloud System Controller,"
+                " disallowing use of entire management subnet.  "
+                "Ensure management ip range does not include System"
+                " Controller gateway address(es)", 80)
 
         if not self.use_entire_mgmt_subnet:
             while True:
@@ -1183,8 +1192,19 @@ class ConfigAssistant():
                         "Address range must contain at least %d addresses. " %
                         min_addresses)
                     continue
-                break
 
+                sc = sysinv_constants.DISTRIBUTED_CLOUD_ROLE_SYSTEMCONTROLLER
+                if (self.system_dc_role == sc):
+                    # Warn user that some space in the management subnet must
+                    # be reserved for the system controller gateway address(es)
+                    # used to communicate with the subclouds. - 2 because of
+                    # subnet and broadcast addresses.
+                    if address_range.size >= (self.management_subnet.size - 2):
+                        print textwrap.fill(
+                            "Address range too large, no addresses left "
+                            "for System Controller gateway(s). ", 80)
+                        continue
+                break
         while True:
             print
             print textwrap.fill(