Use an event variable to wait for the server to be ready, rather than sleep(0.1).
diff --git a/Lib/test/test_telnetlib.py b/Lib/test/test_telnetlib.py
index 0a3604e..c48de04 100644
--- a/Lib/test/test_telnetlib.py
+++ b/Lib/test/test_telnetlib.py
@@ -7,12 +7,13 @@
 from test import test_support
 
 
-def server(evt):
+def server(evt, ready):
     serv = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
     serv.settimeout(3)
     serv.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
     serv.bind(("", 9091))
     serv.listen(5)
+    ready.set()
     try:
         conn, addr = serv.accept()
     except socket.timeout:
@@ -25,8 +26,9 @@
 
     def setUp(self):
         self.evt = threading.Event()
-        threading.Thread(target=server, args=(self.evt,)).start()
-        time.sleep(.1)
+        ready = threading.Event()
+        threading.Thread(target=server, args=(self.evt, ready)).start()
+        ready.wait()
 
     def tearDown(self):
         self.evt.wait()