Question

Difficulty: MediumIP Addressing and Network Configuration

A technician is configuring network parameters on a newly installed workstation. Upon reviewing the network interface details, the technician observes that the system has automatically assigned itself an IPv6 address of fe80::5054:ff:fe12:3456fe80::5054:ff:fe12:3456. The host can successfully communicate with neighboring systems connected to the same physical switch, but cannot reach devices on external subnets or the internet. Which of the following best explains why the workstation is unable to communicate beyond its local network segment?

  1. A
    The workstation is using an APIPA address because the local IPv6 DHCP server was unreachable during startup.
  2. The host is configured with a link-local IPv6 address, which routers will not forward outside the local network segment.Answer
  3. C
    An unmanaged switch is required to translate link-local IPv6 frames into routable Layer 3 packets.
  4. D
    The workstation relies on a DNS server to dynamically convert the link-local IPv6 address into a routable lease.

Answer

The host has only been assigned a link-local IPv6 address (fe80::/10fe80::/10), which is restricted to the immediate network segment and cannot be forwarded by routers to external subnets.
IPv6 link-local addresses starting with the prefix fe80::/10fe80::/10 are restricted to communication within a single physical or virtual link. Routers automatically drop traffic originating from or addressed to link-local addresses, preventing communication beyond the local segment until a routable address is configured.

Step-by-Step Solution

1
Identify the prefix of the assigned IPv6 address.
The address fe80::5054:ff:fe12:3456fe80::5054:ff:fe12:3456 begins with fe80::fe80::, placing it in the fe80::/10fe80::/10 range.
Addresses within this block are auto-generated IPv6 link-local addresses.
2
Determine the scope and routing capability of link-local addresses.
Link-local addresses are restricted to a single link or broadcast domain.
Routers are designed to drop packets with link-local source or destination addresses.
3
Identify what is necessary for inter-subnet communication.
The workstation requires a Global Unicast Address assigned statically, via SLAAC, or via DHCPv6.
Global Unicast Addresses provide publicly/privately routable scope across routers.

Key Concept

IPv6 Link-Local Addressing Scope (fe80::/10fe80::/10)
Estimated Time:1m 0s
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