Your company has a main office and two branch offices. The offices connect to each other by using a WAN
link.
In the main office, you have a server named Server1that runs Windows Server 2012.
Server1 is configured to use an IPv4 address only.
You need to assign an IPv6 address to Server1. The IP address must be private and routable.
Which IPv6 address should you assign to Server1?
A.
ff00:3fff:65df:145c:dca8::82a4
B.
2001:ab32:145c::32cc:401b
C.
fe80:ab32:145c::32cc:401b
D.
fd00:ab32:14:ad88:ac:58:abc2:4
Explanation:
pg 266 Chapter 6 : Installing and Configuring Windows Server 2012 Unique local addresses
Unique local addresses are IPv6 addresses that are private to an organization in the same way that private
addresses–such as 10.x.x.x, 192.168.x.x, or 172.16.0.0 – 172.31.255.255–can be used on an IPv4 network.
Unique local addresses, therefore, are not routableon the IPv6 Internet in the same way that an address like
10.20.100.55 is not routable on the IPv4 Internet.
A unique local address is always structured as follows:
The first 8 bits are always 11111101 in binary format. This means that a unique local address always begins
with FD and has a prefix identifier of FD00::/8.
Good table, I have noted FD00 isn’t even listed! Nice one!
Explanation says “Unique local address is not routable”. QUestion says “must be routable”…
Plus many tutorial say that “unique local” is FC00.
I am so confused with this question and with IPV6…:-((
FC00 and FD00 are both unique local.Unique local addresses are private and routable. They’re equivalent to IPv4 private addresses.
The correct answer is D.
Explanation:
“Unique local unicasts addresses are the IPv6 equivalent of IPv4 private addresses. These
addresses are routable within an organization, but not on the Internet.
IPv4 private IP addresses were a relatively small part of the overall IPv4 address space, and many companies used the same address space. This caused problems when separate organizations tried to communicate directly. It also caused problems when merging the networks of two organizations, such as after a merger or buyout.
To avoid the duplication problems experienced with IPv4 private addresses, the IPv6 unique local address structure allocates 40 bits to an organization identifier. The 40-bit organization identifier is generated randomly, and the likelihood of two randomly generated identical 40-bit identifiers is very small. This ensures that each organization has a unique address space.
The first 7 bits of the organization identifier have the fixed binary value of 1111110. All unique local addresses have the address prefix of FC00::/7. The Local (L) flag (the 8th bit) is set to 1 to indicate a local address. An L flag value set to 0 has not yet been defined. Therefore, unique local addresses with the L flag set to 1 have the address prefix of FD::/8.”
Unique Local Address(ULA) is not routable on the IPv6 “Internet”, thus making it private. And it is routable to private networks.
Probably, this is what they mean:
A. ff00….<–we can't use it, it's multicast
B. 2001…<–we can't use it, it's "aggregated global unicast"
C. fe80…<–we can't use it's "link local"
D. FD00…<–the only option is left, doesn't belong to any group
Explanation with the table of addresses above doesn't make any sense…
B would also be correct
The ULA prefix is fc00::/7. But the 8th most-significant-bit (MSB) determines which “half” of the allocation a prefix is being assigned from, fc00::/8 or fd00::/8. According to the RFC 4193 “Unique Local IPv6 Unicast Addresses,” this bit indicates a locally assigned prefix when set to 1 and is undefined when set to 0. Thus, technically only prefixes from fd00::/8 should be defined and used.
https://community.infoblox.com/t5/IPv6-CoE-Blog/3-Ways-to-Ruin-Your-Future-Network-with-IPv6-Unique-Local/ba-p/5663