在一台Cisco由器的g3/1端口封禁端口号139的TCP和端口号为43的UDP连接,并封禁ICMP协议。只允许212.15.41.0/26子网的ICMP数据包通过路由器,正确配置是
A.
Router(config)#ip access-list extended filterRouter(config-ext-nacl)#permit icmp 212.15.41.0.0.0.0.192 anyRouter(config-ext-nacl)#deny icmp any anyRouter(config-ext-nacl)#deny udp any any eq 1434Router(config-ext-nacl)#deny tcp any any eq 139Router(config-ext-nacl)t#permit ip any anyRouter(config-ext-nacl)#exitRonter(config)#interface g3/1Router(config-if)#ip access-group filter inRouter(config-if)#ip access-group filter out
B.
Router(config)#ip access-list standard filterRouter(config-std-nacl)#permit icmp 212.15.41.0.0.0.0.63 anyRouter(config-std-nacl)#deny icmp any anyRouter(conig-std-nacl)#deny ndp any any eq 1434Router(config-std-nacl)#deny tcp any any eq 139Router(config-std-nacl)#permit ip any anyRouter(config-std-nacl)#exitRonter(config)#interface g3/1Router(config-if)#ip access-group filter inRouter(config-if)#ip access-group filter out
C.
Router(config)#ip access-list extended filterRouter(config-ext-nacl)#permit icmp 212.15.41.0.255.255.255.192 anyRouter(config-ext-nacl)#deny icmp any anyRouter(config-ext-nacl)#deny udp any any eq 1434Router(config-ext-nacl)#deny tcp any any eq 139Router(config-ext-nacl)t#permit ip any anyRouter(config-ext-nacl)#exitRonter(config)#interface g3/1Router(config-if)#ip access-group filter inRouter(config-if)#ip access-group filter out
D.
Router(config)#ip access-list extended filterRouter(config-std-nacl)#permit icmp 212.15.41.0.0.0.0.63 anyRouter(config-std-nacl)#deny icmp any anyRouter(conig-std-nacl)#deny ndp any any eq 1434Router(config-std-nacl)#deny tcp any any eq 139Router(config-std-nacl)#permit ip any anyRouter(config-std-nacl)#exitRonter(config)#interface g3/1Router(config-if)#ip access-group filter inRouter(config-if)#ip access-group filter out