A.Router(config)#access-list 110 permit icmp 212.78.170.166 0.0.0.0 any Router(config)#access-list 110 deny icmp any any Router(config)#access-list 110 permit ip any any
B.Router(config)#access-list 110 permit icmp 212.78.170.0 255.255.255.224 any Router(config)#access-list 110 permit ip any any Router(config)#access-list 110 deny icmp any any
C.Router(config)#access-list 110 perimt icmp 212.78.170.0 0.0.0.255 any Router(config)#access-list 110 deny icmp any any Router(config)#access-list 110 permit ip any any
D.Router(config)#access-list 110 permit icmp 212.78.170.160 0.0.0.31 any Router(config)#access-list 110 deny icmp any any Router(config)#access-list 110 permit ip any any
39. 在一台主机上朋浏览器无法访问到域名为www.yinfu.edu.cn的网站,并且在这台主机上执行tracert命令时有如下信息: Tracing route to www.yinfu.edu.cn[202.113.96.10] Over maximum of 30 hops: 1<1ms<1ms<1ms 59.67.148.1 259.67.148.1 reports:Destination net unreachable Trace complete 分析以上信息,会造成这种现象的原因是______。