diff --git a/include/libtorrent/aux_/session_impl.hpp b/include/libtorrent/aux_/session_impl.hpp
index 1d97a9d12..826e9cf7e 100644
--- a/include/libtorrent/aux_/session_impl.hpp
+++ b/include/libtorrent/aux_/session_impl.hpp
@@ -646,7 +646,7 @@ namespace aux {
 			void stop_natpmp();
 			void stop_upnp();
 
-			port_mapping_t add_port_mapping(portmap_protocol t, int external_port
+			std::vector<port_mapping_t> add_port_mapping(portmap_protocol t, int external_port
 				, int local_port);
 			void delete_port_mapping(port_mapping_t handle);
 
diff --git a/include/libtorrent/session_handle.hpp b/include/libtorrent/session_handle.hpp
index b06fe078f..fb737de14 100644
--- a/include/libtorrent/session_handle.hpp
+++ b/include/libtorrent/session_handle.hpp
@@ -1012,7 +1012,7 @@ namespace libtorrent {
 		// whichever is enabled. The return value is a handle referring to the
 		// port mapping that was just created. Pass it to delete_port_mapping()
 		// to remove it.
-		port_mapping_t add_port_mapping(portmap_protocol t, int external_port, int local_port);
+		std::vector<port_mapping_t> add_port_mapping(portmap_protocol t, int external_port, int local_port);
 		void delete_port_mapping(port_mapping_t handle);
 
 		// This option indicates if the ports are mapped using natpmp
diff --git a/src/session_handle.cpp b/src/session_handle.cpp
index bf93a5cd7..bd87aa21f 100644
--- a/src/session_handle.cpp
+++ b/src/session_handle.cpp
@@ -1226,10 +1226,10 @@ namespace {
 	}
 #endif // TORRENT_ABI_VERSION
 
-	port_mapping_t session_handle::add_port_mapping(portmap_protocol const t
+	std::vector<port_mapping_t> session_handle::add_port_mapping(portmap_protocol const t
 		, int external_port, int local_port)
 	{
-		return sync_call_ret<port_mapping_t>(&session_impl::add_port_mapping, t, external_port, local_port);
+		return sync_call_ret<std::vector<port_mapping_t>>(&session_impl::add_port_mapping, t, external_port, local_port);
 	}
 
 	void session_handle::delete_port_mapping(port_mapping_t handle)
diff --git a/src/session_impl.cpp b/src/session_impl.cpp
index 974a7177d..93488a8d5 100644
--- a/src/session_impl.cpp
+++ b/src/session_impl.cpp
@@ -6696,17 +6696,17 @@ namespace aux {
 		return m_upnp.get();
 	}
 
-	port_mapping_t session_impl::add_port_mapping(portmap_protocol const t
+	std::vector<port_mapping_t> session_impl::add_port_mapping(portmap_protocol const t
 		, int const external_port
 		, int const local_port)
 	{
-		port_mapping_t ret{-1};
-		if (m_upnp) ret = m_upnp->add_mapping(t, external_port
-			, tcp::endpoint({}, static_cast<std::uint16_t>(local_port)));
+		std::vector<port_mapping_t> ret;
+		if (m_upnp) ret.push_back(m_upnp->add_mapping(t, external_port
+			, tcp::endpoint({}, static_cast<std::uint16_t>(local_port))));
 		for (auto& s : m_listen_sockets)
 		{
-			if (s->natpmp_mapper) ret = s->natpmp_mapper->add_mapping(t, external_port
-				, tcp::endpoint({}, static_cast<std::uint16_t>(local_port)));
+			if (s->natpmp_mapper) ret.push_back(s->natpmp_mapper->add_mapping(t, external_port
+				, tcp::endpoint({}, static_cast<std::uint16_t>(local_port))));
 		}
 		return ret;
 	}