Destination Net Unreachable：表示对方主机不存在或者没有跟对方建立连接。
Destination Net Unreachable：表示对方主机不存在或者没有跟对方建立连接。
Which of the following will generate an ICMP message? A: Unreachable destination B: The TTL value of a packet reaches zero C: Echo request D: All of the choices
Which of the following will generate an ICMP message? A: Unreachable destination B: The TTL value of a packet reaches zero C: Echo request D: All of the choices
In Hu Wenzhong's theory of An Iceberg of Culture, only a small part of culture is______ and______ while most of it is invisible and intangible. A: unreachable B: visible C: superficial D: unforgetable
In Hu Wenzhong's theory of An Iceberg of Culture, only a small part of culture is______ and______ while most of it is invisible and intangible. A: unreachable B: visible C: superficial D: unforgetable
一台计算机的IP地址为211.34.114.254，使用标准掩码，未设置网关，Ping211.34.113.3，回应为（） A: Reply？form？211.34.113.3：bytes=32？time=2ms？TTL=255 B: Request？timed？out C: Destination？Host？Unreachable D: Reply？from？211.34.113.3：？Destinatio
一台计算机的IP地址为211.34.114.254，使用标准掩码，未设置网关，Ping211.34.113.3，回应为（） A: Reply？form？211.34.113.3：bytes=32？time=2ms？TTL=255 B: Request？timed？out C: Destination？Host？Unreachable D: Reply？from？211.34.113.3：？Destinatio
一台计算机的IP地址为211.34.114.254，使用标准掩码，未设置网关，Ping211.34.113.3，回应为（） A: Reply？form？211.34.113.3：bytes=32？time=2ms？TTL=255 B: Request？timed？out C: Destination？Host？Unreachable D: Reply？from？211.34.113.3：？Destination
一台计算机的IP地址为211.34.114.254，使用标准掩码，未设置网关，Ping211.34.113.3，回应为（） A: Reply？form？211.34.113.3：bytes=32？time=2ms？TTL=255 B: Request？timed？out C: Destination？Host？Unreachable D: Reply？from？211.34.113.3：？Destination
Which of the followings is incorrect？（ ） A: Bird-in-hand Principle means, to start your business, the resources that you have already owned are better than unreachable resources. B: Affordable Loss Principle suggests evaluating your affordable loss in advance. C: Lemonade Principle encourages entrepreneurs to be negative when encountering difficulties. D: It is important to realize that contingencies will happen in the process of creating a business.
Which of the followings is incorrect？（ ） A: Bird-in-hand Principle means, to start your business, the resources that you have already owned are better than unreachable resources. B: Affordable Loss Principle suggests evaluating your affordable loss in advance. C: Lemonade Principle encourages entrepreneurs to be negative when encountering difficulties. D: It is important to realize that contingencies will happen in the process of creating a business.
在IPv4和IPv6的转换中，以下关于6to4协议说法正确的两项是（） A: 由于6to4协议对IPv4路由没有影响，该协议在IPv4中不会引起路由环路 B: 如果IPv6包的MTU超过了IPv4包的MTU，那么该IPv6包会在6to4路由器上丢弃 C: 6to4路由器可能不会返回包含“unreachable”消息的ICMPv6报文到源端的IPv6节点 D: 存在于6to4边界路由器上的防火墙和NAT通常不会影响6to4的机制
在IPv4和IPv6的转换中，以下关于6to4协议说法正确的两项是（） A: 由于6to4协议对IPv4路由没有影响，该协议在IPv4中不会引起路由环路 B: 如果IPv6包的MTU超过了IPv4包的MTU，那么该IPv6包会在6to4路由器上丢弃 C: 6to4路由器可能不会返回包含“unreachable”消息的ICMPv6报文到源端的IPv6节点 D: 存在于6to4边界路由器上的防火墙和NAT通常不会影响6to4的机制