Replaced boolean tests with is None.
diff --git a/Lib/telnetlib.py b/Lib/telnetlib.py
index 656e97b..4c806db 100644
--- a/Lib/telnetlib.py
+++ b/Lib/telnetlib.py
@@ -186,7 +186,7 @@
         self.cookedq = ''
         self.eof = 0
         self.option_callback = None
-        if host:
+        if host is not None:
             self.open(host, port)
 
     def open(self, host, port=0):