diff --git a/tests/cli/ursula/test_run_ursula.py b/tests/cli/ursula/test_run_ursula.py
index 344767574..f8e8519e9 100644
--- a/tests/cli/ursula/test_run_ursula.py
+++ b/tests/cli/ursula/test_run_ursula.py
@@ -15,15 +15,21 @@ You should have received a copy of the GNU Affero General Public License
 along with nucypher.  If not, see <https://www.gnu.org/licenses/>.
 """
 
-import pytest_twisted as pt
 import time
+
+import pytest
+import pytest_twisted as pt
 from twisted.internet import threads
 
 from nucypher.characters.base import Learner
+from nucypher.cli import actions
 from nucypher.cli.main import nucypher_cli
 from nucypher.config.node import NodeConfiguration
-from nucypher.utilities.sandbox.constants import INSECURE_DEVELOPMENT_PASSWORD, \
-    MOCK_URSULA_STARTING_PORT, TEMPORARY_DOMAIN
+from nucypher.utilities.sandbox.constants import (
+    INSECURE_DEVELOPMENT_PASSWORD,
+    MOCK_URSULA_STARTING_PORT,
+    TEMPORARY_DOMAIN
+)
 from nucypher.utilities.sandbox.ursula import start_pytest_ursula_services
 
 
@@ -108,3 +114,69 @@ def test_ursula_cannot_init_with_dev_flag(click_runner):
     result = click_runner.invoke(nucypher_cli, init_args, catch_exceptions=False)
     assert result.exit_code == 2
     assert 'Cannot create a persistent development character' in result.output, 'Missing or invalid error message was produced.'
+
+
+def test_ursula_rest_host_determination(click_runner):
+
+    # Patch the get_external_ip call
+    original_call = actions.get_external_ip
+    actions.get_external_ip = lambda: '192.0.2.0'
+
+    args = ('ursula', 'init',
+            '--federated-only',
+            '--network', TEMPORARY_DOMAIN
+            )
+
+    user_input = f'Y\n{INSECURE_DEVELOPMENT_PASSWORD}\n{INSECURE_DEVELOPMENT_PASSWORD}'
+
+    breakpoint()
+    result = click_runner.invoke(nucypher_cli, args, catch_exceptions=False,
+                                 input=user_input)
+
+    assert result.exit_code == 0
+    assert '(192.0.2.0)' in result.output
+
+    args = ('ursula', 'init',
+            '--federated-only',
+            '--network', TEMPORARY_DOMAIN,
+            '--force'
+            )
+
+    user_input = f'{INSECURE_DEVELOPMENT_PASSWORD}\n{INSECURE_DEVELOPMENT_PASSWORD}\n'
+
+    result = click_runner.invoke(nucypher_cli, args, catch_exceptions=False,
+                                 input=user_input)
+
+    assert result.exit_code == 0
+    assert 'IP 192.0.2.0' in result.output
+
+    # Patch get_external_ip call to error output
+    actions.get_external_ip = lambda: None
+
+    args = ('ursula', 'init',
+            '--federated-only',
+            '--network', TEMPORARY_DOMAIN,
+            '--force'
+            )
+
+    user_input = f'{INSECURE_DEVELOPMENT_PASSWORD}\n{INSECURE_DEVELOPMENT_PASSWORD}\n'
+    with pytest.raises(RuntimeError):
+        result = click_runner.invoke(nucypher_cli, args, catch_exceptions=True,
+                                     input=user_input)
+
+    # Patch get_external_ip call to return bad IP
+    actions.get_external_ip = lambda: '382.328.382.328'
+
+    args = ('ursula', 'init',
+            '--federated-only',
+            '--network', TEMPORARY_DOMAIN,
+            '--force'
+            )
+
+    user_input = f'{INSECURE_DEVELOPMENT_PASSWORD}\n{INSECURE_DEVELOPMENT_PASSWORD}\n'
+    with pytest.raises(OSError):
+        result = click_runner.invoke(nucypher_cli, args, catch_exceptions=True,
+                                     input=user_input)
+
+    # Unpatch call
+    actions.get_external_ip = original_call