The following configuration 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 destination 2.2.2.2
tunnel mode ipv6ip
ipv6 eigrp 1

A.
Automatic 6to4

B.
Manually configured tunnel

C.
ISATAP

D.
GRE

Explanation:
A manually configured tunnel explicitly defines the destination IPv4 address, as does a GRE
IPv6 tunnel. The other two types listed in the answer do not. Additionally, a manually
configured tunnel uses mode ipv6ip, whereas GRE tunnels use mode gre.