diff --git a/nucypher/characters/base.py b/nucypher/characters/base.py
index 2345b99b2..516e831e8 100644
--- a/nucypher/characters/base.py
+++ b/nucypher/characters/base.py
@@ -104,6 +104,8 @@ class Character(Learner):
 
         #
         # Operating Mode
+        #
+
         if hasattr(self, '_interface_class'):  # TODO: have argument about meaning of 'lawful'
             #                                         and whether maybe only Lawful characters have an interface
             self.interface = self._interface_class(character=self)
diff --git a/nucypher/characters/lawful.py b/nucypher/characters/lawful.py
index a7711cf09..6efe10be8 100644
--- a/nucypher/characters/lawful.py
+++ b/nucypher/characters/lawful.py
@@ -17,7 +17,7 @@ along with nucypher.  If not, see <https://www.gnu.org/licenses/>.
 
 
 import json
-from collections import OrderedDict
+from collections import OrderedDict, defaultdict
 
 import contextlib
 import maya
@@ -39,7 +39,6 @@ from constant_sorrow.constants import (
     READY,
     INVALIDATED
 )
-from collections import OrderedDict, defaultdict
 from cryptography.hazmat.backends import default_backend
 from cryptography.hazmat.primitives.asymmetric.ec import EllipticCurve
 from cryptography.hazmat.primitives.serialization import Encoding
@@ -59,7 +58,6 @@ from typing import Dict, Iterable, List, Tuple, Union, Optional, Sequence, Set
 from umbral import pre
 from umbral.keys import UmbralPublicKey
 from umbral.kfrags import KFrag
-from umbral.pre import UmbralCorrectnessError
 from umbral.signing import Signature
 
 import nucypher
@@ -101,6 +99,7 @@ from nucypher.network.protocols import InterfaceInfo, parse_node_uri
 from nucypher.network.server import ProxyRESTServer, TLSHostingPower, make_rest_app
 from nucypher.network.trackers import AvailabilityTracker
 from nucypher.utilities.logging import Logger
+from nucypher.utilities.networking import validate_worker_ip
 
 
 class Alice(Character, BlockchainPolicyAuthor):
@@ -1258,9 +1257,13 @@ class Ursula(Teacher, Character, Worker):
             if result > 0:
                 self.log.debug(f"Pruned {result} treasure maps.")
 
+    def __preflight(self) -> None:
+        """Called immediately before running services"""
+        validate_worker_ip(worker_ip=self.rest_interface.host)
+
     def run(self,
             emitter: StdoutEmitter = None,
-            discovery: bool = True,
+            discovery: bool = True,  # TODO: see below
             availability: bool = True,
             worker: bool = True,
             pruning: bool = True,
@@ -1272,6 +1275,8 @@ class Ursula(Teacher, Character, Worker):
 
         """Schedule and start select ursula services, then optionally start the reactor."""
 
+        self.__preflight()
+
         #
         # Async loops ordered by schedule priority
         #
diff --git a/nucypher/cli/actions/configure.py b/nucypher/cli/actions/configure.py
index 196fff46a..3eb6a77a3 100644
--- a/nucypher/cli/actions/configure.py
+++ b/nucypher/cli/actions/configure.py
@@ -37,10 +37,11 @@ from nucypher.cli.literature import (
     COLLECT_URSULA_IPV4_ADDRESS,
     CONFIRM_URSULA_IPV4_ADDRESS
 )
-from nucypher.cli.types import IPV4_ADDRESS
+from nucypher.cli.types import IPV4_ADDRESS, WORKER_IP
 from nucypher.config.characters import StakeHolderConfiguration
 from nucypher.config.constants import NUCYPHER_ENVVAR_WORKER_IP_ADDRESS
 from nucypher.config.node import CharacterConfiguration
+from nucypher.utilities.networking import InvalidWorkerIP, validate_worker_ip
 from nucypher.utilities.networking import determine_external_ip_address, UnknownIPAddress
 
 
@@ -119,12 +120,12 @@ def handle_invalid_configuration_file(emitter: StdoutEmitter,
         raise  # crash :-(
 
 
-def collect_external_ip_address(emitter: StdoutEmitter, network: str, force: bool = False) -> str:
+def collect_worker_ip_address(emitter: StdoutEmitter, network: str, force: bool = False) -> str:
 
     # From environment variable  # TODO: remove this environment variable?
     ip = os.environ.get(NUCYPHER_ENVVAR_WORKER_IP_ADDRESS)
     if ip:
-        message = f'Using IP address from {NUCYPHER_ENVVAR_WORKER_IP_ADDRESS} environment variable'
+        message = f'Using IP address ({ip}) from {NUCYPHER_ENVVAR_WORKER_IP_ADDRESS} environment variable'
         emitter.message(message, verbosity=2)
         return ip
 
@@ -141,8 +142,9 @@ def collect_external_ip_address(emitter: StdoutEmitter, network: str, force: boo
     # Confirmation
     if not force:
         if not click.confirm(CONFIRM_URSULA_IPV4_ADDRESS.format(rest_host=ip)):
-            ip = click.prompt(COLLECT_URSULA_IPV4_ADDRESS, type=IPV4_ADDRESS)
+            ip = click.prompt(COLLECT_URSULA_IPV4_ADDRESS, type=WORKER_IP)
 
+    validate_worker_ip(worker_ip=ip)
     return ip
 
 
@@ -157,7 +159,17 @@ def perform_ip_checkup(emitter: StdoutEmitter, ursula: Ursula, force: bool = Fal
         message = 'Cannot automatically determine external IP address'
         emitter.message(message)
         return  # TODO: crash, or not to crash... that is the question
-    ip_mismatch = external_ip != ursula.rest_interface.host
+    rest_host = ursula.rest_interface.host
+    try:
+        validate_worker_ip(worker_ip=rest_host)
+    except InvalidWorkerIP:
+        message = f'{rest_host} is not a valid or permitted worker IP address.  Set the correct external IP then try again\n' \
+                  f'automatic configuration -> nucypher ursula config ip-address\n' \
+                  f'manual configuration    -> nucypher ursula config --rest-host <IP ADDRESS>'
+        emitter.message(message)
+        return
+
+    ip_mismatch = external_ip != rest_host
     if ip_mismatch and not force:
         error = f'\nX External IP address ({external_ip}) does not match configuration ({ursula.rest_interface.host}).\n'
         hint = f"Run 'nucypher ursula config ip-address' to reconfigure the IP address then try " \
diff --git a/nucypher/cli/commands/ursula.py b/nucypher/cli/commands/ursula.py
index 1c7ce6fa1..2f36f7513 100644
--- a/nucypher/cli/commands/ursula.py
+++ b/nucypher/cli/commands/ursula.py
@@ -18,12 +18,14 @@
 
 import click
 
+from nucypher.blockchain.eth.networks import NetworksInventory
 from nucypher.blockchain.eth.signers.software import ClefSigner
 from nucypher.cli.actions.auth import get_client_password, get_nucypher_password
 from nucypher.cli.actions.configure import (
     destroy_configuration,
     handle_missing_configuration_file,
-    get_or_update_configuration, collect_external_ip_address
+    get_or_update_configuration,
+    collect_worker_ip_address
 )
 from nucypher.cli.actions.configure import forget as forget_nodes, perform_ip_checkup
 from nucypher.cli.actions.select import (
@@ -59,7 +61,7 @@ from nucypher.cli.options import (
     option_max_gas_price
 )
 from nucypher.cli.painting.help import paint_new_installation_help
-from nucypher.cli.types import EIP55_CHECKSUM_ADDRESS, NETWORK_PORT
+from nucypher.cli.types import EIP55_CHECKSUM_ADDRESS, NETWORK_PORT, WORKER_IP
 from nucypher.cli.utils import make_cli_character, setup_emitter
 from nucypher.config.characters import UrsulaConfiguration
 from nucypher.config.constants import (
@@ -176,7 +178,7 @@ class UrsulaConfigOptions:
 
         # Resolve rest host
         if not self.rest_host:
-            self.rest_host = collect_external_ip_address(emitter, network=self.domain, force=force)
+            self.rest_host = collect_worker_ip_address(emitter, network=self.domain, force=force)
 
         return UrsulaConfiguration.generate(password=get_nucypher_password(confirm=True),
                                             config_root=config_root,
@@ -223,10 +225,10 @@ group_config_options = group_options(
     max_gas_price=option_max_gas_price,
     worker_address=click.option('--worker-address', help="Run the worker-ursula with a specified address", type=EIP55_CHECKSUM_ADDRESS),
     federated_only=option_federated_only,
-    rest_host=click.option('--rest-host', help="The host IP address to run Ursula network services on", type=click.STRING),
+    rest_host=click.option('--rest-host', help="The host IP address to run Ursula network services on", type=WORKER_IP),
     rest_port=click.option('--rest-port', help="The host port to run Ursula network services on", type=NETWORK_PORT),
     db_filepath=option_db_filepath,
-    network=option_network(),
+    network=option_network(default=NetworksInventory.DEFAULT),
     registry_filepath=option_registry_filepath,
     poa=option_poa,
     light=option_light,
@@ -422,7 +424,7 @@ def config(general_config, config_options, config_file, force, action):
                                          checksum_address=config_options.worker_address,
                                          config_class=UrsulaConfiguration)
     if action == 'ip-address':
-        rest_host = collect_external_ip_address(emitter=emitter, network=config_options.domain, force=force)
+        rest_host = collect_worker_ip_address(emitter=emitter, network=config_options.domain, force=force)
         config_options.rest_host = rest_host
     updates = config_options.get_updates()
     get_or_update_configuration(emitter=emitter,
diff --git a/nucypher/cli/literature.py b/nucypher/cli/literature.py
index 2ccdd3222..7d47e9691 100644
--- a/nucypher/cli/literature.py
+++ b/nucypher/cli/literature.py
@@ -377,7 +377,7 @@ DECRYPTING_CHARACTER_KEYRING = 'Authenticating {name}'
 
 CONFIRM_URSULA_IPV4_ADDRESS = "Detected IPv4 address ({rest_host}) - Is this the public-facing address of Ursula?"
 
-COLLECT_URSULA_IPV4_ADDRESS = "Enter Ursula's public-facing IPv4 address:"
+COLLECT_URSULA_IPV4_ADDRESS = "Enter Ursula's public-facing IPv4 address"
 
 
 #
diff --git a/nucypher/cli/types.py b/nucypher/cli/types.py
index 763d85451..08dcd2aff 100644
--- a/nucypher/cli/types.py
+++ b/nucypher/cli/types.py
@@ -26,6 +26,7 @@ from nucypher.blockchain.economics import StandardTokenEconomics
 from nucypher.blockchain.eth.interfaces import BlockchainInterface
 from nucypher.blockchain.eth.networks import NetworksInventory
 from nucypher.blockchain.eth.token import NU
+from nucypher.utilities.networking import validate_worker_ip, InvalidWorkerIP
 
 
 class ChecksumAddress(click.ParamType):
@@ -46,12 +47,24 @@ class IPv4Address(click.ParamType):
     def convert(self, value, param, ctx):
         try:
             _address = ip_address(value)
-        except ValueError as e:
+        except ValueError:
             self.fail("Invalid IP Address")
         else:
             return value
 
 
+class WorkerIPAddress(IPv4Address):
+    name = 'worker_ip'
+
+    def convert(self, value, param, ctx):
+        _ip = super().convert(value, param, ctx)
+        try:
+            validate_worker_ip(worker_ip=_ip)
+        except InvalidWorkerIP as e:
+            self.fail(str(e))
+        return value
+
+
 class DecimalType(click.ParamType):
     name = 'decimal'
 
@@ -136,6 +149,7 @@ EXISTING_READABLE_FILE = click.Path(exists=True, dir_okay=False, file_okay=True,
 # Network
 NETWORK_PORT = click.IntRange(min=0, max=65535, clamp=False)
 IPV4_ADDRESS = IPv4Address()
+WORKER_IP = WorkerIPAddress()
 
 GAS_STRATEGY_CHOICES = click.Choice(list(BlockchainInterface.GAS_STRATEGIES.keys()))
 UMBRAL_PUBLIC_KEY_HEX = UmbralPublicKeyHex()
diff --git a/nucypher/config/characters.py b/nucypher/config/characters.py
index e0cc682eb..2f7707061 100644
--- a/nucypher/config/characters.py
+++ b/nucypher/config/characters.py
@@ -39,7 +39,6 @@ class UrsulaConfiguration(CharacterConfiguration):
     CHARACTER_CLASS = Ursula
     NAME = CHARACTER_CLASS.__name__.lower()
 
-    DEFAULT_REST_HOST = '127.0.0.1'
     DEFAULT_REST_PORT = 9151
     DEFAULT_DEVELOPMENT_REST_PORT = 10151
     __DEFAULT_TLS_CURVE = ec.SECP384R1
@@ -48,10 +47,10 @@ class UrsulaConfiguration(CharacterConfiguration):
     LOCAL_SIGNERS_ALLOWED = True
 
     def __init__(self,
+                 rest_host: str,
                  worker_address: str = None,
                  dev_mode: bool = False,
                  db_filepath: str = None,
-                 rest_host: str = None,
                  rest_port: int = None,
                  tls_curve: EllipticCurve = None,
                  certificate: Certificate = None,
@@ -64,7 +63,7 @@ class UrsulaConfiguration(CharacterConfiguration):
             else:
                 rest_port = self.DEFAULT_REST_PORT
         self.rest_port = rest_port
-        self.rest_host = rest_host or self.DEFAULT_REST_HOST
+        self.rest_host = rest_host
         self.tls_curve = tls_curve or self.__DEFAULT_TLS_CURVE
         self.certificate = certificate
         self.db_filepath = db_filepath or UNINITIALIZED_CONFIGURATION
diff --git a/nucypher/network/nodes.py b/nucypher/network/nodes.py
index 020aa6907..bc6713df2 100644
--- a/nucypher/network/nodes.py
+++ b/nucypher/network/nodes.py
@@ -245,8 +245,7 @@ class Learner:
 
         from nucypher.characters.lawful import Ursula
         self.node_class = node_class or Ursula
-        self.node_class.set_cert_storage_function(
-            node_storage.store_node_certificate)  # TODO: Fix this temporary workaround for on-disk cert storage.  #1481
+        self.node_class.set_cert_storage_function(node_storage.store_node_certificate)  # TODO: Fix this temporary workaround for on-disk cert storage.  #1481
 
         known_nodes = known_nodes or tuple()
         self.unresponsive_startup_nodes = list()  # TODO: Buckets - Attempt to use these again later  #567
diff --git a/nucypher/utilities/networking.py b/nucypher/utilities/networking.py
index 3a7311b80..973528ae8 100644
--- a/nucypher/utilities/networking.py
+++ b/nucypher/utilities/networking.py
@@ -16,16 +16,15 @@
 """
 
 
-from ipaddress import ip_address
-
 import random
 import requests
+from ipaddress import ip_address
 from requests.exceptions import RequestException, HTTPError
 from typing import Union
 
-from nucypher.blockchain.eth.registry import BaseContractRegistry, InMemoryContractRegistry
+from nucypher.config.storages import LocalFileBasedNodeStorage
 from nucypher.acumen.perception import FleetSensor
-from nucypher.characters.lawful import Ursula
+from nucypher.blockchain.eth.registry import BaseContractRegistry, InMemoryContractRegistry
 from nucypher.network.middleware import RestMiddleware, NucypherMiddlewareClient
 from nucypher.utilities.logging import Logger
 
@@ -34,6 +33,10 @@ class UnknownIPAddress(RuntimeError):
     pass
 
 
+class InvalidWorkerIP(RuntimeError):
+    """Raised when an Ursula is using an invalid IP address for it's server."""
+
+
 RequestErrors = (
     # https://requests.readthedocs.io/en/latest/user/quickstart/#errors-and-exceptions
     ConnectionError,
@@ -42,9 +45,22 @@ RequestErrors = (
     HTTPError
 )
 
+RESERVED_IP_ADDRESSES = (
+    '0.0.0.0',
+    '127.0.0.1',
+    '1.2.3.4'
+)
+
 IP_DETECTION_LOGGER = Logger('external-ip-detection')
 
 
+
+def validate_worker_ip(worker_ip: str) -> None:
+    if worker_ip in RESERVED_IP_ADDRESSES:
+        raise InvalidWorkerIP(f'{worker_ip} is not a valid or permitted worker IP address.  '
+                              f'Verify the rest_host is set to the external IPV4 address')
+
+
 def __request(url: str, certificate=None) -> Union[str, None]:
     """
     Utility function to send a GET request to a URL returning it's
@@ -65,6 +81,8 @@ def get_external_ip_from_default_teacher(network: str,
                                          log: Logger = IP_DETECTION_LOGGER,
                                          registry: BaseContractRegistry = None
                                          ) -> Union[str, None]:
+    from nucypher.characters.lawful import Ursula
+
     if federated_only and registry:
         raise ValueError('Federated mode must not be true if registry is provided.')
     base_error = 'Cannot determine IP using default teacher'
@@ -76,13 +94,19 @@ def get_external_ip_from_default_teacher(network: str,
     except KeyError:
         log.debug(f'{base_error}: Unknown network "{network}".')
         return
-    if not registry:
-        # Registry is needed to perform on-chain staking verification.
-        registry = InMemoryContractRegistry.from_latest_publication(network=network)
+
+    ####
+    # TODO: Clean this mess #1481
+    node_storage = LocalFileBasedNodeStorage(federated_only=federated_only)
+    Ursula.set_cert_storage_function(node_storage.store_node_certificate)
+    Ursula.set_federated_mode(federated_only)
+    #####
+
     teacher = Ursula.from_teacher_uri(teacher_uri=top_teacher_url,
-                                      registry=registry,
                                       federated_only=federated_only,
                                       min_stake=0)  # TODO: Handle customized min stake here.
+
+    # TODO: Pass registry here to verify stake (not essential here since it's a hardcoded node)
     client = NucypherMiddlewareClient()
     try:
         response = client.get(node_or_sprout=teacher, path=f"ping", timeout=2)  # TLS certificate logic within
@@ -97,6 +121,8 @@ def get_external_ip_from_default_teacher(network: str,
             raise UnknownIPAddress(error)
         log.info(f'Fetched external IP address from default teacher ({top_teacher_url} reported {ip}).')
         return ip
+    else:
+        log.debug(f'Failed to get external IP from teacher node ({response.status_code})')
 
 
 def get_external_ip_from_known_nodes(known_nodes: FleetSensor,