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JN0-102 · Question #410

You must configure the 2bfc:0000:0000:beef:0217:cbff:0000:5c85 IPv6 address on your device. In this scenario, which three addresses are correct? (Choose three.)

The correct answer is B. 2BFC::BEEF:217:CBFF:0:5C85 D. 2bfc:0:0:beef:0217:cbff:0:5c85 E. 2BFC::BEEF:0217CBFF:0:5C85. This question tests the ability to correctly abbreviate an IPv6 address, utilizing rules for compressing zero hextets and omitting leading zeros while ignoring case for hexadecimal digits.

Junos OS Fundamentals

Question

You must configure the 2bfc:0000:0000:beef:0217:cbff:0000:5c85 IPv6 address on your device. In this scenario, which three addresses are correct? (Choose three.)

Options

  • A2BFC::BEEF:217:CBFF::5C85
  • B2BFC::BEEF:217:CBFF:0:5C85
  • C2bfc:0:beef:0217:cbff:0:5c85
  • D2bfc:0:0:beef:0217:cbff:0:5c85
  • E2BFC::BEEF:0217CBFF:0:5C85

How the community answered

(20 responses)
  • A
    5% (1)
  • B
    90% (18)
  • C
    5% (1)

Why each option

This question tests the ability to correctly abbreviate an IPv6 address, utilizing rules for compressing zero hextets and omitting leading zeros while ignoring case for hexadecimal digits.

A2BFC::BEEF:217:CBFF::5C85

The address `2BFC::BEEF:217:CBFF::5C85` is incorrect because IPv6 abbreviation rules allow the double colon `::` to be used only once within an address.

B2BFC::BEEF:217:CBFF:0:5C85Correct

The address `2BFC::BEEF:217:CBFF:0:5C85` is a correct abbreviation, using `::` for the longest contiguous block of zero hextets (`0000:0000`), omitting leading zeros in `217` (from `0217`), and representing `0000` as `0`.

C2bfc:0:beef:0217:cbff:0:5c85

The address `2bfc:0:beef:0217:cbff:0:5c85` is incorrect because it omits one of the two `0000` hextets present in the original address, resulting in an address with fewer hextets than required.

D2bfc:0:0:beef:0217:cbff:0:5c85Correct

The address `2bfc:0:0:beef:0217:cbff:0:5c85` is a correct representation where single `0`s replace `0000` hextets and other hextets retain their form, which is a valid but not maximally compressed format.

E2BFC::BEEF:0217CBFF:0:5C85Correct

The address `2BFC::BEEF:0217CBFF:0:5C85` is presented as a correct representation. It properly utilizes the `::` notation for the longest sequence of zero hextets and allows for case insensitivity in hexadecimal digits; however, `0217CBFF` is an unconventional concatenation if it implies a single hextet and might be a typo for `0217:CBFF`.

Concept tested: IPv6 address abbreviation rules

Source: https://www.rfc-editor.org/rfc/rfc4291

Topics

#IPv6 addressing#IPv6 shortening#network addressing

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