IPv6 First Hop Security for Registered Locations
The network administrator must implement IPv6 in the network to allow only devices that not only have registered IP addresses but are also connecting from assigned locations. Which security feature must be implemented?
Community Insight
The question requires a feature that validates both the IP address and the physical location (port/VLAN) of the connecting device, pointing towards a mechanism that checks against a dynamic binding table.
This question tests the selection of IPv6 First Hop Security features required to enforce that devices connect from assigned locations with registered IP addresses. The correct implementation is DHCPv6 Guard (often referred to as IPv6 Prefix Guard in this specific exam context) which utilizes the binding table.
Many learners choose IPv6 Destination Guard because it also uses a binding table but filters based on MAC addresses rather than verifying the registration process via DHCP/SLAAC interactions in the same way. Others mistakenly select Router Advertisement Guard, which only prevents rogue advertisements and does not verify client identity or location.
Community Discussion (5 comments)
Comments & Corrections
No comments yet — spotted an error or have a note? Share it below.
Expert Analysis
Why the Answer Is Correct
The requirement to allow devices that have 'registered IP addresses' and are 'connecting from assigned locations' describes the function of DHCPv6 Guard (listed here as IPv6 Prefix Guard). This feature operates by monitoring DHCPv6 messages and maintaining a database of bindings between IPv6 addresses, MAC addresses, and VLAN/interface information. When a packet arrives, the switch verifies if the source address matches an entry in this binding table, ensuring the device is using a legitimately assigned address at that specific port.Why the Other Options Are Wrong
IPv6 Destination Guard filters traffic based on the destination IP and MAC address, primarily preventing IP spoofing, but it does not inherently manage the 'registration' aspect of the IP address assignment process itself. IPv6 Router Advertisement Guard protects against rogue RAs but does not validate individual client connections or their assigned IPs. IPv6 Snooping is a broader term often associated with Neighbor Discovery Inspection, which builds the binding table but is the underlying mechanism rather than the enforcement policy described.Community Comment Notes
Community consensus is divided. User Zizu007 confirms option D, citing Cisco documentation regarding IPv6 Security. However, users like XxnightwingxX argue for B, noting that Destination Guard uses the binding table too. Another user points out that IPv6 Snooping bundles these features. Despite the confusion, the specific phrasing 'registered IP' strongly implies the use of the binding table created by guard mechanisms like DHCPv6 Guard (Prefix Guard).Official Reference
Exam Strategy
When you see keywords like 'registered', 'binding table', and 'assigned locations' in IPv6 security questions, prioritize DHCPv6 Guard or its equivalent name (Prefix Guard) over simple filtering mechanisms like RA Guard or Destination Guard.
Frequently Asked Questions
Why is IPv6 Prefix Guard preferred over Destination Guard?
Prefix Guard (DHCPv6 Guard) specifically manages the registration of IPs via DHCP/SLAAC and binds them to ports, whereas Destination Guard focuses on filtering based on existing bindings without managing the registration.
Does IPv6 Snooping provide the same security?
No, IPv6 Snooping (ND Inspection) helps build the binding table but does not actively drop packets from unregistered sources at the edge in the same enforcement manner as the Guard features.
Related Analysis
Practice All 300-410 Questions
Access 159 questions with complete answers and detailed explanations.
View Full 300-410 Practice Test →