单项选择题 The following configura tion exists on a router on one end of an IPv6 tunnel. Which type of tunnel is created by this configuration?（） interface loopback 1 ip address 1.1.1.1 255.255.255.255 interface tunnel 2 ipv6 address 2000::1::/64 tunnel source loopback 1 tunnel destina tion 2.2.2.2 tunnel mode ipv6ip ipv6 eigrp 1

单项选择题 A client host uses IPv4 to communicate with one ser ver and IPv6 to communicate with another.Which of the following IPv6 coexistence features is likely at work on the host?（）

单项选择题 An enterprise has plans to start adding IPv6 support. The initial deployment requires support from some IPv6 - only device s that need to access servers that support only IPv4. Which of the following tools would be most appropriate?（）