问题详情

用扩展访问控制列表配置封禁ICMP协议，只允许l68．27．95．0／24子网的ICMP数据包通过路由器，正确的配置是(61) 。

A．access-list 90 deny icmp l68．27．95．0 255．255．255．0 any access-list 90 deny icmp any anyaccess—list 90 permit ip any any

B．access-list l00 permit icmp l68．27．95．0 0．0．0．255 any access-list l00 permit ip any any

C．access—list l l o permit icmp l68．27．95．0 255．255．255．0 any access—list l lo deny icmp any any

D．access-list l20 permit icmp l68．27．95．0 0．0．0．255 any access—list l20 deny icmp any any access—list l20 permit ip any any