diff --git a/setup.py b/setup.py
index bb97a94..83a6ae8 100644
--- a/setup.py
+++ b/setup.py
@@ -29,7 +29,7 @@ def stamp_api_version():
 
 setup(
     name="science-synapse",
-    version="2.8.3",
+    version="2.8.4",
     description="Client library and CLI for the Synapse API",
     author="Science Team",
     author_email="team@science.xyz",
diff --git a/synapse/cli/__main__.py b/synapse/cli/__main__.py
index 99554aa..01236f8 100755
--- a/synapse/cli/__main__.py
+++ b/synapse/cli/__main__.py
@@ -38,7 +38,8 @@ def setup_device_uri(args):
     if not args.uri:
         # User doesn't want to use something that needs a uri
         return args
-    if not is_valid_ip(args.uri):
+    # Device accepts ip:port, so only the host part decides name vs address.
+    if not (is_valid_ip(args.uri) or is_valid_ip(args.uri.rsplit(":", 1)[0])):
         # User passed in a name
         console = Console()
         device_ip = find_device_by_name(args.uri, console, False, 60)
diff --git a/synapse/tests/cli/test_uri.py b/synapse/tests/cli/test_uri.py
new file mode 100644
index 0000000..f37219c
--- /dev/null
+++ b/synapse/tests/cli/test_uri.py
@@ -0,0 +1,21 @@
+import importlib.util
+from argparse import Namespace
+from pathlib import Path
+
+import synapse.cli
+
+# conftest.py stubs synapse.cli.__main__, so load the real file under another name.
+_spec = importlib.util.spec_from_file_location(
+    "synapse_cli_main_for_test", Path(synapse.cli.__file__).with_name("__main__.py")
+)
+cli_main = importlib.util.module_from_spec(_spec)
+_spec.loader.exec_module(cli_main)
+
+
+def test_ip_with_port_skips_name_lookup(monkeypatch):
+    def fail(*a, **k):
+        raise AssertionError("name lookup should not run")
+
+    monkeypatch.setattr(cli_main, "find_device_by_name", fail)
+    for uri in ["127.0.0.1", "127.0.0.1:50051", "::1"]:
+        assert cli_main.setup_device_uri(Namespace(uri=uri)).uri == uri