Index: src/OptionHandlerFactory.cc
===================================================================
--- src/OptionHandlerFactory.cc	(revision 2067)
+++ src/OptionHandlerFactory.cc	(working copy)
@@ -168,7 +168,7 @@
     SharedHandle<OptionHandler> op(new BooleanOptionHandler
                                    (PREF_DISABLE_IPV6,
                                     TEXT_DISABLE_IPV6,
-                                    V_FALSE,
+                                    V_TRUE,
                                     OptionHandler::OPT_ARG));
     op->addTag(TAG_ADVANCED);
     handlers.push_back(op);