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Zorluk: Çok zorIPv6 Address Types and EUI-64

A network technician observes an automatically configured Link-Local IPv6 address of FE80::0250:56FF:FE9A:BCDE on a server's network interface using SLAAC and EUI-64. Based on standard EUI-64 interface identifier rules, which two statements regarding this interface's physical MAC address and link-local generation process are correct? (Select two.)

  1. The original burned-in MAC address of the interface is 00:50:56:9A:BC:DE.Cevap
  2. The 7th bit (Universal/Local bit) of the MAC address's first byte was inverted from 0 to 1 during EUI-64 processing to indicate a modified interface ID.Cevap
  3. C
    The original burned-in MAC address of the interface is 02:50:56:9A:BC:DE.
  4. D
    The EUI-64 process inserted the hex sequence FFFF into the exact midpoint of the 48-bit MAC address.

Cevap

The original burned-in MAC address of the interface is 00:50:56:9A:BC:DE, and the 7th bit (Universal/Local bit) of the MAC address's first byte was inverted from 0 to 1 during EUI-64 processing.
The link-local IPv6 address FE80::0250:56FF:FE9A:BCDE uses an EUI-64 interface identifier created from a 48-bit MAC address. EUI-64 inserts the hexadecimal value FFFE into the middle of the MAC address (between the 3rd and 4th bytes) and flips the 7th bit of the first byte (the Universal/Local bit). Reversing this process on 0250:56FF:FE9A:BCDE requires removing FFFE to leave 02:50:56:9A:BC:DE, and flipping the 7th bit of the first byte 02 (0000 0010 in binary) back to 0, which gives 00 (0000 0000 in binary). Thus, the original MAC address is 00:50:56:9A:BC:DE, and the 7th bit was inverted from 0 to 1 during the process.

Adım Adım Çözüm

1
Analyze the 64-bit interface identifier portion of the IPv6 address.
Interface ID is 0250:56FF:FE9A:BCDE.
The link-local prefix is FE80::/64, leaving the last 64 bits as the EUI-64 identifier.
2
Identify and remove the inserted midpoint 16-bit hex sequence.
Removing FFFE from 0250:56FF:FE9A:BCDE yields the 48-bit sequence 02:50:56:9A:BC:DE.
EUI-64 generation inserts FFFE between the 24-bit OUI and the 24-bit device identifier.
3
Invert the 7th bit (Universal/Local bit) of the first byte.
First byte 02 (binary 0000 0010) inverted at the 7th bit becomes 00 (binary 0000 0000). The resulting original MAC address is 00:50:56:9A:BC:DE.
IEEE EUI-64 rule requires flipping the 7th bit (0 for universal scope becomes 1 for local interface ID uniqueness).

Anahtar Kavram

EUI-64 Interface Identifier Derivation
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