单项选择题
A. The Frame Relay PVC is down.
B. The IP addressing on the Central/Remote serial link is incorrect.
C. RIP routing information is not being forwarded.
D. Frame Relay inverse-ARP is not properly configured.
单项选择题 While troubleshooting a serial line problem, you enable ppp authentication debugging as shown below: Based on the command output above, what type of handshake was used for PPP authentication?（）
单项选择题 After attempting to telnet into a router, you are denied and you receive the error message "password required, but none set." What configuration changes will allow telnet access into this router?（）
单项选择题 Which wild card mask will enable a network administrator to permit access to the Internet for only hosts that are assigned an address in the range 192.168.8.0 through 192.168.15.255?（）
