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Question 115

A network engineer must implement an IPv6 configuration on the vlan 2000 interface to create a routable locally-unique unicast address that is blocked from being advertised to the internet. Which configuration must the engineer apply?

    Correct Answer: B

    The correct configuration must use a Unique Local Address (ULA), which falls within the fd00::/8 prefix. These addresses are designed for local use within an organization and are not routable on the public internet. The given address, fd00::1234:2343/64, is a ULA and meets the requirement of being a routable locally-unique unicast address that is blocked from being advertised to the internet.

Discussion
cyborg7Option: B

D is incorrect as it contains :: which replaced with 0000.0000 will make the address longer than 128bits Correct is B

Sacuxipo

fc00 : 0000 : aaaa :: a15d : 1234 : 2343 : 8aca 1st 2nd 3rd 5th 6th 7th 8th I separated in this way to show you that it´is missing the 4th hextet. Guess where it must be? D is correct man.

Dutch012

if there is one all-0 quartet, don't use '::', just put one 0 instead. so the correct one is B.

molly_zheng

RFC4291 recommended that " The use of "::" indicates one or more groups of 16 bits of zeros." refer to https://www.rfc-editor.org/rfc/rfc4291.html

Madzonga

it should also be the leftmost if there are two sets of 0s of equal length and in this address there's a group of 16 bits of zeros to the left of ::

FALARASTA

You should refer the use of :: it means a a whole hextet but all are zeros

jayanga

you are wrong man

Frasema

You can shorten the '0000' by :: It's not must to have '0000:0000' to use ::

Bl1024Option: B

D is wrong address is too long

lmmujsiOption: B

Diretly from CISCO book: NOTE Just to be completely exact, IANA actually reserves prefix FC00::/7, and not FD00::/8, for these addresses. FC00::/7 includes all addresses that begin with hex FC and FD. However, an RFC (4193) requires the eighth bit of these addresses to be set to 1, which means that in practice today, the unique local addresses all begin with their first two digits as FD

xtraMiles

Agree and upvoting. Per RFC 4193 Section 3.1, "...[zero] my be defined in the future," and Section 3.2.2; Line Item 6 regarding setting the "L" bit to 1, hence the FD. Though the prefix starts w/ FC, application is done using FD.

rasadebayorOption: D

The answer to this question is D Here's why: ff00::: These addresses are reserved for multicast purposes and cannot be used for unicast routing. So, option A is incorrect. fd00::: These addresses are unique local addresses (ULA) but are globally routable. So, option B is incorrect. fe80::: These addresses are link-local addresses and cannot be routed outside the local link. So, option C is incorrect. fc00::: These addresses are unique local addresses (ULA) with a globally unique interface identifier (GUID). They are not advertised to the internet by default due to the privacy extension mechanism, while still being routable within the local network. This matches the requirements of the scenario.

Nmk173

Hello. Can you give me any source that says fd00:: is globally routable. I think it can not be globally routable.

PaddyInNZOption: B

Option 'b' is correct. Wow - a lot of confusion here! Options 'b' and 'd' are technically correct - it has nothing to do with IPv6 address length. It's just a matter of which one is "more correct"? ULA is defined as FC00::/7, *however* FC00::/8 is not defined, only FD00::/8 is. For this reason, the answer is 'b'.

Cyber15Option: B

B. interface vlan 2000 ipv6 address fd00::1234:2343/64 Explanation: fd00::/8: This is the Unique Local Address (ULA) prefix. It is reserved for local use and is not routable on the public Internet. ULAs are suitable for creating private IPv6 addresses within an organization.

AbdullahMohammad251Option: B

I think the correct answer is B because in option D we didn't omit the preceding zeros of the 2nd octet, the ipv6 address should be written as fc00:0:aaaa::a15d:1234:2343:8aca/64

AbdullahMohammad251

Also, the double colon is used to represent two or more octets of continuous zeros, this will make our IP address consisting of more than 128 bits

Da_CostaOption: B

B is the right answer

cybercerberesOption: B

Nothing other's

leoooooOption: D

I just tested on lab. It seems that the address fc00 : 0000 : aaaa :: a15d : 1234 : 2343 : 8aca is legitimate and the command "do show int" shows the interface use the ip without any error . I vote for D.

leooooo

I just run answer B to the same interface and command "show ipv6 interface brief" shows the two address. I changed my mind. I will choose answer B because B seems to be a more formal answer according to the discussion.

emredemircioOption: B

what the... it is surely B

sabsyedOption: D

d is correct

BTK0311Option: B

Options A, C, and D do not provide a ULA address. Option D includes an address from the Unique Local Address (ULA) range but also includes a global routing prefix (fc00::/7), which is not typically used for ULAs and may lead to confusion or potential routing issues. Therefore, option B is the correct choice for creating a routable locally-unique unicast address that is not advertised to the Internet.

9c9566bOption: D

To create a locally-unique unicast IPv6 address that is not routable on the internet, the engineer should use a Unique Local Address (ULA), which falls within the fc00::/7 prefix. Therefore, option D is the correct choice: D. interface vlan 2000 ipv6 address fc00:0000:aaaa::a15d:1234:2343:8aca/64

SeMo0o0oOption: B

B. interface vlan 2000 ipv6 address fd00::1234:2343/64 is correct

squagmireOption: D

D is correct, the '::' == 0000. that makes it 16 bytes which is 128bits furthermore, it can only be unique-local because it has to be routable within the network(like private ipv4 addresses). one more thing, fc00::/7 is the only one that would be correct as well, cuz thats the start of a unique-local address

DempsterOption: B

B is totally correct because it is the most abbreviated. But then again, maybe I'm wrong. Who knows? gg good day Go Dodgers