As a network administrator, you have been instructed to prevent all traffic originating on the LAN from entering the R2 router. Which the following command would implement the access list on the interface of the R2 router?（）

单项选择题A network administrator wants to add a line to an access list that will block only Telnet access by the hosts on subnet 192.168.1.128 28 to the server at 192.168.1.5. What command should be issued to accomplish this task?（）

A. access-list 101 deny tcp 192.168.1.128 0.0.0.15 192.168.1.5 0.0.0.0 eq 23 access-list 101 permit ip any any
B. access-list 101 deny tcp 192.168.1.128 0.0.0.240 192.168.1.5 0.0.0.0 eq 23 access-list 101 permit ip any any
C. access-list 1 deny tcp 192.168.1.128 0.0.0.255 192.168.1.5 0.0.0.0 eq 21 access-list 1 permit ip any any
D. access-list 1 deny tcp 192.168.1.128 0.0.0.15 host 192.168.1.5 eq 23 access-list 1 permit ip any any

单项选择题Which protocol is an open standard protocol framework that is commonly used in VPNs,to provid secure end-to-end communication?（）

A. L2TP
B. IPsec
C. PPTP
D. RSA

单项选择题What is one benefit of PVST+?（）

A. PVST+reduces the CPU cycles for all the switches in the network
B. PVST+automatically selects the root bridge location,to provide optimized bandwidth usage.
C. PVST+allow the root switch location to be optimized per vlan.
D. PVST+supports Layer 3 load balancing without loops.

单项选择题Which item represents the standard IP ACL?（）

A. access-list 50 deny 192.168.1.1 0.0.0.255
B. access-list 110 permit ip any any
C. access-list 2500 deny tcp any host 192.168.1.1 eq 22
D. access-list 101 deny tcp any host 192.168.1.1

单项选择题Which statement about access lists that are applied to an interface is true?（）

A. you can apply multiple access lists with the same protocol or in different direction.
B. you can config one access list,per direction,per layer 3 protocol
C. you can place as many access lists as you want on any interface
D. you can apply only one access list on any interface