diff --git a/lib/socket.c b/lib/socket.c
index d1874f0..8083bbb 100644
--- a/lib/socket.c
+++ b/lib/socket.c
@@ -79,7 +79,7 @@ static void release_local_port(uint32_t port)
 		return;
 	
 	nr = port >> 22;
-	used_ports_map[nr / 32] &= ~((nr % 32) + 1);
+	used_ports_map[nr / 32] &= ~(1 << nr % 32);
 }
 
 /**