diff --git a/server/tests/test_config_portability.py b/server/tests/test_config_portability.py
index 9dc964f..fea3d55 100644
--- a/server/tests/test_config_portability.py
+++ b/server/tests/test_config_portability.py
@@ -23,6 +23,8 @@ def test_save_and_load_utf8_lf(tmp_path: Path) -> None:
         max_players=8,
         log_verbosity="info",
         admin_port=7779,
+        enable_gns_transport=True,
+        gns_bridge_path="/opt/commonwealth/libcommonwealth_online_gns_bridge.so",
     )
     save_config(cfg, str(path))
 
@@ -34,6 +36,28 @@ def test_save_and_load_utf8_lf(tmp_path: Path) -> None:
     assert loaded.server_name == "Café Server"
     assert loaded.server_description == "résumé"
     assert loaded.admin_port == 7779
+    assert loaded.enable_gns_transport is True
+    assert loaded.gns_bridge_path == "/opt/commonwealth/libcommonwealth_online_gns_bridge.so"
+
+
+def test_gns_boolean_config_parsing_does_not_treat_false_string_as_true() -> None:
+    assert Config.from_dict({"enable_gns_transport": "false"}).enable_gns_transport is False
+    assert Config.from_dict({"enable_gns_transport": "off"}).enable_gns_transport is False
+    assert Config.from_dict({"enable_gns_transport": "0"}).enable_gns_transport is False
+    assert Config.from_dict({"enable_gns_transport": "true"}).enable_gns_transport is True
+    assert Config.from_dict({"enable_gns_transport": "yes"}).enable_gns_transport is True
+    assert Config.from_dict({"enable_gns_transport": 1}).enable_gns_transport is True
+    assert Config.from_dict({"enable_gns_transport": 0}).enable_gns_transport is False
+    with pytest.raises(ValueError, match="enable_gns_transport"):
+        Config.from_dict({"enable_gns_transport": "sometimes"})
+
+
+def test_gns_bridge_path_normalizes_blank_to_none_and_rejects_nonstring() -> None:
+    assert Config.from_dict({"gns_bridge_path": ""}).gns_bridge_path is None
+    assert Config.from_dict({"gns_bridge_path": "   "}).gns_bridge_path is None
+    assert Config.from_dict({"gns_bridge_path": None}).gns_bridge_path is None
+    with pytest.raises(ValueError, match="gns_bridge_path"):
+        Config.from_dict({"gns_bridge_path": 123})
 
 
 def test_validate_rejects_bad_ports_and_max_players() -> None:
@@ -56,6 +80,21 @@ def test_validate_rejects_unresolvable_host() -> None:
     assert any("not a valid IPv4" in error for error in errors)
 
 
+def test_gns_requires_explicit_ipv4_bind_host() -> None:
+    explicit = Config(host="127.0.0.1", enable_gns_transport=True)
+    ok, errors = validate_config(explicit)
+    assert ok, errors
+
+    wildcard = Config(host="0.0.0.0", enable_gns_transport=True)
+    ok, errors = validate_config(wildcard)
+    assert ok, errors
+
+    hostname = Config(host="localhost", enable_gns_transport=True)
+    ok, errors = validate_config(hostname)
+    assert not ok
+    assert any("explicit IPv4 bind address" in error for error in errors)
+
+
 def test_ensure_writable_directory(tmp_path: Path) -> None:
     target = tmp_path / "state"
     ensure_writable_directory(target)