Topic: 200-301 topic 1 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?

A.
interface vlan 2000 ipv6 address ff00:0000:aaaa::1234:2343/64
B.
interface vlan 2000 ipv6 address fd00::1234:2343/64
C.
interface vlan 2000 ipv6 address fe80:0000:aaaa::1234:2343/64
D.
interface vlan 2000 ipv6 address fc00:0000:aaaa::a15d:1234:2343:8aca/64

Re: 200-301 topic 1 question 115

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

Re: 200-301 topic 1 question 115

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

Re: 200-301 topic 1 question 115

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.

Re: 200-301 topic 1 question 115

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

Re: 200-301 topic 1 question 115

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

Re: 200-301 topic 1 question 115

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

Re: 200-301 topic 1 question 115

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 ::

Re: 200-301 topic 1 question 115

you are wrong man

Re: 200-301 topic 1 question 115

D is wrong address is too long

Re: 200-301 topic 1 question 115

d is correct

Re: 200-301 topic 1 question 115

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.

Re: 200-301 topic 1 question 115

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

Re: 200-301 topic 1 question 115

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

Re: 200-301 topic 1 question 115

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

Re: 200-301 topic 1 question 115

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

Re: 200-301 topic 1 question 115

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.

Re: 200-301 topic 1 question 115

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

Re: 200-301 topic 1 question 115

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'.

Re: 200-301 topic 1 question 115

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.

Re: 200-301 topic 1 question 115

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

Re: 200-301 topic 1 question 115

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

Re: 200-301 topic 1 question 115

B is the right answer

Re: 200-301 topic 1 question 115

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

Re: 200-301 topic 1 question 115

I think it's B