Command for Generating IPv6 Address from Prefix and MAC Address

C.

The ipv6 address autoconfig command causes the device to perform IPv6 stateless address auto-configuration to discover prefixes on the link and then to add the EUI-64 based addresses to the interface.

Addresses are configured depending on the prefixes received in Router Advertisement (RA) messages.

The device will listen for RA messages which are transmitted periodically from the router (DHCP Server)

This RA message allows a host to create a global IPv6 address from: Its interface identifier (EUI-64 address) Link Prefix (obtained via RA) Note: Global address is the combination of Link Prefix and EUI-64 address.

The command that automatically generates an IPv6 address from a specified IPv6 prefix and MAC address of an interface is:

B. ipv6 address 2001:DB8:5:112::/64 eui-64

Explanation:

• "ipv6 address": This command is used to assign an IPv6 address to an interface.
• "2001:DB8:5:112::/64": This is the IPv6 prefix that will be used for the interface. The /64 at the end means that this is a prefix length of 64 bits, which is the standard for IPv6 subnets.
• "eui-64": This keyword tells the router to use the modified EUI-64 format to generate the interface ID portion of the IPv6 address. The EUI-64 format takes the MAC address of the interface and inserts FF:FE in the middle, and then flips the 7th bit. This creates a unique interface ID that is easy to generate and remember.

Using this command will automatically generate an IPv6 address for the interface based on the specified prefix and the MAC address of the interface. The resulting address will be in the form of "2001:DB8:5:112:xxxx:xxxx:xxxx:xxxx", where the "xxxx" portions represent the interface ID generated using the EUI-64 format.

Option A, "ipv6 address dhcp", would assign an IPv6 address to the interface using DHCPv6, which is a method of dynamically assigning IPv6 addresses to clients. Option C, "ipv6 address autoconfig", enables stateless address autoconfiguration on the interface, which allows the interface to automatically configure its own IPv6 address based on the network prefix advertised by a router on the network. Option D, "ipv6 address 2001:DB8:5:112::2/64 link-local", assigns a link-local IPv6 address to the interface, which is used for local communication on the same link and does not require a router.