diff --git a/src/natpmp.cpp b/src/natpmp.cpp
index 4f642599e..d9ec42beb 100644
--- a/src/natpmp.cpp
+++ b/src/natpmp.cpp
@@ -58,6 +58,7 @@ natpmp::natpmp(io_service& ios, address const& listen_interface, portmap_callbac
 	, m_refresh_timer(ios)
 	, m_next_refresh(-1)
 	, m_disabled(false)
+	, m_abort(false)
 {
 	rebind(listen_interface);
 }
@@ -298,13 +299,18 @@ void natpmp::send_map_request(int i)
 	error_code ec;
 	m_socket.send_to(asio::buffer(buf, 12), m_nat_endpoint, 0, ec);
 	m.map_sent = true;
-	// linear back-off instead of exponential
 	if (m_abort)
 	{
+		// when we're shutting down, ignore the
+		// responses and just remove all mappings
+		// immediately
+		m_currently_mapping = -1;
+		m.action = mapping_t::action_none;
 		try_next_mapping(i);
 	}
 	else
 	{
+		// linear back-off instead of exponential
 		++m_retry_count;
 		m_send_timer.expires_from_now(milliseconds(250 * m_retry_count), ec);
 		m_send_timer.async_wait(bind(&natpmp::resend_request, self(), i, _1));