diff --git a/include/libtorrent/session.hpp b/include/libtorrent/session.hpp
index f2f107780..3fee69802 100644
--- a/include/libtorrent/session.hpp
+++ b/include/libtorrent/session.hpp
@@ -239,6 +239,8 @@ namespace libtorrent
 			pack.set_int(settings_pack::max_retry_port_bind, listen_port_range.second - listen_port_range.first);
 			pack.set_str(settings_pack::peer_fingerprint, print.to_string());
 			char if_string[100];
+
+			if (listen_interface == NULL) listen_interface = "0.0.0.0";
 			snprintf(if_string, sizeof(if_string), "%s:%d", listen_interface, listen_port_range.first);
 			pack.set_str(settings_pack::listen_interfaces, if_string);
 
diff --git a/src/session.cpp b/src/session.cpp
index 9d3913fda..e844bff29 100644
--- a/src/session.cpp
+++ b/src/session.cpp
@@ -355,7 +355,7 @@ namespace libtorrent
 		::_set_se_translator(straight_to_debugger);
 #endif
 
-		bool internal_executor = ios == NULL;
+		bool const internal_executor = ios == NULL;
 
 		if (internal_executor)
 		{
diff --git a/src/session_impl.cpp b/src/session_impl.cpp
index 2892a63d8..15495bb56 100644
--- a/src/session_impl.cpp
+++ b/src/session_impl.cpp
@@ -464,7 +464,10 @@ namespace aux {
 	// post it to the io_service?
 	void session_impl::start_session(settings_pack const& pack)
 	{
-		m_alerts.set_alert_mask(pack.get_int(settings_pack::alert_mask));
+		if (pack.has_val(settings_pack::alert_mask))
+		{
+			m_alerts.set_alert_mask(pack.get_int(settings_pack::alert_mask));
+		}
 
 #ifndef TORRENT_DISABLE_LOGGING
 		session_log("start session");