diff --git a/src/tests/client/test-client.py b/src/tests/client/test-client.py
index 82c2919963..b6f7cf00a4 100755
--- a/src/tests/client/test-client.py
+++ b/src/tests/client/test-client.py
@@ -2160,18 +2160,14 @@ class TestNmCloudSetup(TestNmClient):
             # hallucinogenic substances.
             s.listen(5)
 
-            def pass_socket():
-                os.dup2(s.fileno(), 3)
-
             service_path = PathConfiguration.test_cloud_meta_mock_path()
             env = os.environ.copy()
-            env["LISTEN_FDS"] = "1"
+            env["LISTEN_FD"] = str(s.fileno())
             p = subprocess.Popen(
                 [sys.executable, service_path],
                 stdin=subprocess.PIPE,
                 env=env,
                 pass_fds=(s.fileno(),),
-                preexec_fn=pass_socket,
             )
 
             self.md_url = "http://%s:%d" % s.getsockname()
diff --git a/tools/test-cloud-meta-mock.py b/tools/test-cloud-meta-mock.py
index 262dc2ffb3..392955b8ad 100755
--- a/tools/test-cloud-meta-mock.py
+++ b/tools/test-cloud-meta-mock.py
@@ -68,11 +68,9 @@ class SocketHTTPServer(HTTPServer):
 
 
 # See sd_listen_fds(3)
-fileno = os.getenv("LISTEN_FDS")
+fileno = os.getenv("LISTEN_FD")
 if fileno is not None:
-    if fileno != "1":
-        raise Exception("Bad LISTEN_FDS")
-    s = socket.socket(fileno=3)
+    s = socket.socket(fileno=int(fileno))
 else:
     addr = ("localhost", 0)
     s = socket.socket()