Document that SSL v2 is insecure.
diff --git a/Doc/library/ssl.rst b/Doc/library/ssl.rst
index c69fac4..e802381 100644
--- a/Doc/library/ssl.rst
+++ b/Doc/library/ssl.rst
@@ -237,6 +237,10 @@
 
    Selects SSL version 2 as the channel encryption protocol.
 
+   .. warning::
+
+      SSL version 2 is insecure.  Its use is highly discouraged.
+
 .. data:: PROTOCOL_SSLv23
 
    Selects SSL version 2 or 3 as the channel encryption protocol.  This is a