When a router is powered on, the router reads the configuration file saved in the default save directory to get itself initialized. If the configuration file does not exist in the default save directory, what does the router use to initialize itself?

As shown in the figure, the RTA uses NAT technology and implements a many-to-many non-NAPT address translation by defining an address pool, so that hosts on the private network can access the public network. Assume that there are only two public IP addresses in the address pool, and the addresses have been assigned to hosts A and
B. If host C also wants to access the public network, which of the following description is correct?

As shown in the following figure, the router uses the sub-interface as the gateway of the host. The IP address of the gateway is 10.0.12.2. Which of the following commands can fulfill this requirement? (Multiple Choice)

NAPT uses the same public IP address but different port numbers to translate private IP addresses. Which statement regarding the port number is correct?

The Protocol field in the PPP frame format is 0xC223, indicating that the protocol is: