A data-center VLAN is numbered with the global unicast prefix 2001:db8:22:10::/64. The router's interface on that VLAN is configured as the default gateway 2001:db8:22:10::1/64. You are manually assigning a static IPv6 address to a new application server on this subnet. Which of the following addresses is valid for the server and follows common addressing conventions?
Falls inside the same /64 prefix as the subnet (2001:db8:22:10::/64) and
Does not duplicate the router's gateway address and
Is not a special-purpose (e.g., link-local) prefix.
2001:db8:22:10::25/64 satisfies these conditions: it retains the full 64-bit network prefix and chooses a unique host identifier (::25).
Why the other choices are wrong:
2001:db8:22:10::1/64 duplicates the gateway address, which would break connectivity.
fe8025/64 is a link-local address (FE80/10) that is not routed beyond the local link and is never used for static global assignments.
2001:db8:22::25/64 is outside the required subnet; missing the "10" hextet places it in a different /64 and the host would not reach the intended gateway.