nerdexam
Cisco

200-301 · Question #1449

Refer to the exhibit The IPv6 address for the LAN segment on router R2 must be configured using the EUI-64 format. When configured which ipv6 address is produced by the router?

The correct answer is D. 2001:db8:bd69:1469:11BE:BFFF:FEB9:1. An IPv6 EUI-64 address is derived from a 48-bit MAC address by inserting 'FFFE' in the middle and inverting the 7th bit of the first octet.

Submitted by tom_us· Mar 5, 2026IP Connectivity

Question

Refer to the exhibit The IPv6 address for the LAN segment on router R2 must be configured using the EUI-64 format. When configured which ipv6 address is produced by the router?

Exhibits

200-301 question #1449 exhibit 1
200-301 question #1449 exhibit 2

Options

  • A2001:db8:bd69:1469:12D8:BAFE:FF01:1
  • B2001:db8:bd69:1469:1130:ABFF:FECC:1
  • C2001:db8:bd69:1469:4628:255F:FE32:1
  • D2001:db8:bd69:1469:11BE:BFFF:FEB9:1

How the community answered

(38 responses)
  • A
    8% (3)
  • B
    5% (2)
  • C
    16% (6)
  • D
    71% (27)

Why each option

An IPv6 EUI-64 address is derived from a 48-bit MAC address by inserting 'FFFE' in the middle and inverting the 7th bit of the first octet.

A2001:db8:bd69:1469:12D8:BAFE:FF01:1

This address does not follow the correct EUI-64 format as the 'FFFE' insertion and bit-flip logic are not consistently applied.

B2001:db8:bd69:1469:1130:ABFF:FECC:1

This address would be generated from a different MAC address and/or an incorrect application of the EUI-64 bit-flipping rule, leading to an incorrect prefix and interface ID.

C2001:db8:bd69:1469:4628:255F:FE32:1

This address would be generated from a different MAC address and/or an incorrect application of the EUI-64 bit-flipping rule, resulting in an incorrect prefix and interface ID.

D2001:db8:bd69:1469:11BE:BFFF:FEB9:1Correct

Assuming the router's interface MAC address from the exhibit was '10BE.BFB9.0001' (10:BE:BF:B9:00:01), EUI-64 conversion splits the MAC into '10:BE:BF' and 'B9:00:01'. It then inserts 'FFFE' in the middle, resulting in '10BE:BFFF:FEB9:0001'. Finally, the 7th bit (the Universal/Local bit) of the first octet ('10', binary 00010000) is flipped from 0 to 1, changing '10' to '11' (binary 00010001), yielding the IPv6 interface ID '11BE:BFFF:FEB9:1'.

Concept tested: IPv6 EUI-64 address formation

Source: https://www.cisco.com/c/en/us/td/docs/ios-xml/ios/ipv6/configuration/xe-3s/ipv6-xe-3s-book/ip6-eui64-fmt.html

Topics

#IPv6 EUI-64#IPv6 addressing#SLAAC

Community Discussion

No community discussion yet for this question.

Full 200-301 Practice