diff --git a/channels/testing/live.py b/channels/testing/live.py
index cb2a7c494..87bf9b729 100644
--- a/channels/testing/live.py
+++ b/channels/testing/live.py
@@ -37,14 +37,15 @@ class ChannelsLiveServerTestCase(TransactionTestCase):
     ProtocolServerProcess = DaphneProcess
     static_wrapper = ASGIStaticFilesHandler
     serve_static = True
+    port = 0
 
     @property
     def live_server_url(self):
-        return "http://%s:%s" % (self.host, self._port)
+        return "http://%s:%s" % (self.host, self.port)
 
     @property
     def live_server_ws_url(self):
-        return "ws://%s:%s" % (self.host, self._port)
+        return "ws://%s:%s" % (self.host, self.port)
 
     @classmethod
     def setUpClass(cls):
@@ -69,6 +70,7 @@ def setUpClass(cls):
             cls.host,
             get_application,
             setup=set_database_connection,
+            port=cls.port,
         )
         cls._server_process.start()
         while True:
diff --git a/docs/topics/testing.rst b/docs/topics/testing.rst
index c3547fd85..783a842f1 100644
--- a/docs/topics/testing.rst
+++ b/docs/topics/testing.rst
@@ -362,6 +362,12 @@ standard Django ``LiveServerTestCase``:
             },
         }
 
+port
+~~~~
+
+Subclass ``ChannelsLiveServerTestCase`` with ``port = {port_number}`` to bind
+both the HTTP and WebSocket servers to a specific port. 
+
 serve_static
 ~~~~~~~~~~~~
 
diff --git a/setup.cfg b/setup.cfg
index 09232fefe..9fb103daf 100644
--- a/setup.cfg
+++ b/setup.cfg
@@ -44,7 +44,7 @@ tests =
     pytest-asyncio
     selenium
 daphne =
-    daphne>=4.0.0
+    daphne>=4.2.1
 
 [options.packages.find]
 exclude =