定义一个用于封禁ICMP协议而只允许转发166.129.130.0/24子网的ICMP数据包的访问控制列表,Cisco路由器的正确配置是( )。

admin2021-06-16  38

问题 定义一个用于封禁ICMP协议而只允许转发166.129.130.0/24子网的ICMP数据包的访问控制列表,Cisco路由器的正确配置是(    )。

选项 A、access-list 198 permit icmp 166.129.130.0 255.255.255.0 any
   access-list 198 deny icmp any any
   access-list 198 permit ip any any
B、access-list 198 permit icmp 166.129.130.0 0.0.0 255 any
   access-list 198 deny icmp any any
   access-list 198 permit ip any any
C、access-list 99 permit icmp 166.129.130.0 0.0.0 255 any
   access-list 99 deny icmp any any
   access-list 99 permit ip any any
D、access-list 100 permit icmp 166.129.130.0 0.0.0 255 any
   access-list 100 permit ip any any
   access-list 100 deny icmp any any

答案B

解析 封禁ICMP协议属于配置扩展访问控制列表,所以表号范围为100~199或2000~2699,格式为:access-list access-list-number {permit|deny} protocol source wildcard-mask destination wildcard-mask [operator] [operand]。因为wildcard-mask为子网掩码的反码,所以根据以上描述,本题选项B)正确。
转载请注明原文地址:https://kaotiyun.com/show/CwOZ777K
0

相关试题推荐
最新回复(0)