单项选择题 A network engineer wants to allow a temporary entry for a remote user with a specific usename and password so that the user can access the entire network over the internet.which ACL can be used?（）

单项选择题 Which term describes a spanning-tree network that has all switch ports in either the blocking or forwarding state?（）

单项选择题 Which PPP subprotocol negotiates authentication options?（）