200-301 Question 93
Single answerA network administrator is configuring IPv6 addressing on a router interface. The administrator assigns the address 2001:db8:abcd:0010::1/64 to the interface and verifies that it is functioning correctly by pinging another IPv6 device on the same network. However, the administrator notices that the router automatically generates a second IPv6 address for the interface. What is the most likely cause of this behavior?
- A
The router is using stateless address autoconfiguration (SLAAC) to generate a link-local address.
- B
The router is configured with both a manual IPv6 address and a DHCPv6 address.
- C
The router automatically assigns a link-local address to the interface in addition to the configured IPv6 address.
- D
The router is configured with IPv6 multicast addressing, which generates an additional address.
Show answer and explanation
Correct answer: C
Explanation
In IPv6, every interface is automatically assigned a link-local address (in the FE80::/10 range) regardless of whether additional global unicast or other types of addresses are manually configured. This behavior ensures that the interface can participate in local communication, such as routing protocols, even if no global address is assigned. The presence of a manually configured address does not suppress the automatic generation of the link-local address.
- A. Incorrect.
This is incorrect because SLAAC is used for generating global unicast addresses, not link-local addresses, which are automatically assigned regardless of SLAAC.
- B. Incorrect.
This is incorrect as there is no indication of DHCPv6 being configured, and the behavior described is standard for IPv6 interfaces.
- C. Correct.
This is correct because IPv6 interfaces automatically generate a link-local address (in the FE80::/10 range) in addition to any manually configured or DHCP-assigned global unicast addresses.
- D. Incorrect.
This is incorrect because IPv6 multicast addresses are not generated automatically for an interface; they are predefined based on the needs of multicast communication.