启动日志中出现 user.emerg syslog: Another app is currently holding the xtables lock. Perhaps you want to use the -w option? 意思是iptable当前被占用，添加失败，要求使用-w参数，参数含义如下： --wait -w wait for the xtables lock 如果不加此参数，则会导致iptables添加失败，应用出现问题