单项选择题在一台Cisco路由器的S0/3端口封禁端口号为4444的TCP数据包,只允许166.105.130.0/24和202.1 12.8.0/30子网的4444端口的TCP数据包通过路由器,正确的access-list配置是( )。
A.Router(config)#ip access-list extended block 4444 Router(config-ext-nacl)#permit tcp166.105.130.0 255.255.255.0 any eq 4444 Router(con6g-ext-nacl)#permit tcp202.112.8.0 255.255.255.252 any eq 4444 Router(config-ext-nacl)#deny tcp any any eq 4444 Router(config-ext-nacl)#permi tip any any Router(config)#interface s0/3 Router(config-if)#ip access-group block 4444 in Router(config-if)#ip access-group block 4444 out
B.Router(config)#ip access-list extended block 4444 Router(config-ext-nacl)#permit 166.105.130.0 0.0.0.255 any tcp eq 4444 Router(config-ext-nael)#permit 202.112.8.0 0.0.0.3 any tcp eq 4444 Router(config-ext-nacl)#deny any any tcp eq 4444 Router(config-ext-nacl)#permit ip any any Router(config)#interface s0/3 Router(config-if)#ip access-group test in Router(config-if)#ip access-group test out
C.Router(config)#ip access-listextended block 4444 Router(coonfig-ext-nacl)#permit tcp 166.105.130.0 0.0.0.255 any eq 4444 Router(config-ext-nacl)#permit tcp 202.112.8.0 0.0.0.3 any eq 4444 Router(config-ext-nacl)#deny tcp any any eq 4444 Router(config-ext-nacl)#permit ip any any Router(config-ext-nacl)#exit Router(config)#interface s0/3 Router(config-if)#ip access-group block 4444 in Router(config-if)#ip access-group block 4444 out
D.Router(config)#ip access-list extended block 4444 Router(config-ext-nacl)#permit tcp 166.105.130.0 0.0.0.255 any eq 4444 Router(config-ext-nacl)#permit tcp 202.112.8.0 0.0.0.3 any eq 4444 Router(config-ext-nacl)#deny tcp any any eq 4444 Router(config-ext-nacl)#permit tcp any any Router(config)#interface s0/3 Router(corffig-if)#ip access-group block 4444 in Router(config-if)#ip access-group block 4444 out