AP Networking IPv6 and Neighbor Discovery Practice Test

1. DHCPv4
2. ARP
3. ICMPv6
4. FTP

Correct answer: C. ICMPv6

Neighbor Discovery uses ICMPv6 messages. IPv4 ARP is not the address-resolution protocol for IPv6.

1. Assign every VLAN
2. Start a TCP stream
3. Create a public DNS zone
4. Discover or verify an on-link neighbor

Correct answer: D. Discover or verify an on-link neighbor

Neighbor Solicitation participates in address resolution and reachability checks. Its role depends on the exchange context.

1. Neighbor address/reachability information
2. An HTTP password
3. A physical cable certification
4. A DHCPv4 scope offer

Correct answer: A. Neighbor address/reachability information

Neighbor Advertisements answer or announce neighbor information under IPv6 ND rules. They are not application responses.

1. TCP FIN
2. ARP request
3. Router Advertisement
4. DNS CNAME

Correct answer: C. Router Advertisement

Router Advertisements provide router-discovery and other link information. Prefix and default-router lifetimes must be interpreted separately.

1. TCP SYN-ACK
2. DNS PTR
3. DHCPv4 ACK
4. Router Solicitation

Correct answer: D. Router Solicitation

A Router Solicitation asks routers to advertise sooner. It is an ICMPv6 control exchange rather than DNS lookup.

1. A switch trunk
2. An IPv4 /24 mask
3. A TLS certificate automatically
4. An IPv6 address using advertised autonomous prefix information and local rules

Correct answer: D. An IPv6 address using advertised autonomous prefix information and local rules

SLAAC supports address formation when the advertised prefix and host requirements permit it. A usable address does not alone prove a default route.

1. Whether every DNS name is unique globally
2. Whether a proposed IPv6 address is already in use on the link
3. Whether a WAN route is shortest
4. Whether TCP has duplicates

Correct answer: B. Whether a proposed IPv6 address is already in use on the link

DAD checks a tentative local address through ND behavior. It does not inventory every remote address.

1. Yes, only on fiber
2. Only when DNS is enabled
3. No
4. Yes, with 128-bit ARP fields

Correct answer: C. No

IPv6 uses Neighbor Discovery over ICMPv6 rather than IPv4 ARP.

1. Every TCP port
2. All DNS names
3. Global unicast everywhere
4. Link-local unicast

Correct answer: D. Link-local unicast

Link-local addresses are scoped to a link and are not ordinarily forwarded by routers beyond it.

1. DNS must convert it to IPv4
2. It is a global router ID
3. The host must select the relevant local link
4. It encodes a TCP port

Correct answer: C. The host must select the relevant local link

A host can have multiple links using link-local scope. The zone identifies which interface/link the destination belongs to.

1. The default route
2. IPv6 loopback
3. All-node multicast
4. A DHCPv6 server group

Correct answer: B. IPv6 loopback

::1 addresses the local host. It cannot demonstrate a working external neighbor or router path.

1. Absence of a specific assigned source/address value
2. A broadcast host
3. A default gateway host
4. A normal remote server

Correct answer: A. Absence of a specific assigned source/address value

The unspecified address has special uses, including certain initialization exchanges. It is not an ordinary assigned endpoint destination.

1. A MAC vendor code
2. Always loopback
3. Multicast
4. Ordinary IPv4 private unicast

Correct answer: C. Multicast

ff00::/8 is IPv6 multicast space. IPv6 uses multicast for relevant one-to-many operations instead of IPv4-style broadcast.

1. PTR only
2. A only
3. AAAA
4. MX only

Correct answer: C. AAAA

AAAA records contain IPv6 addresses. Returning one still does not establish the IPv6 network path.

1. Supporting IPv4 and IPv6
2. Using two DNS names only
3. Using two copper pairs
4. Disabling routing

Correct answer: A. Supporting IPv4 and IPv6

Each address family has its own addressing and path behavior. Success in one is not proof that the other works.

1. How long the sender may serve as a default router under that advertisement
2. The lifetime of every TCP session
3. The lifetime of every DNS record
4. The physical cable warranty

Correct answer: A. How long the sender may serve as a default router under that advertisement

Router lifetime is distinct from prefix and address lifetimes. Read the specific field being discussed.

1. /24
2. /32 as the IPv4 default
3. /64
4. /128 for every client LAN

Correct answer: C. /64

Ordinary SLAAC with common 64-bit interface identifiers uses /64 prefixes. This is not a universal statement that every IPv6 route is /64.

1. The existence of a link-local value
2. Global/remote IPv6 connectivity
3. Some local IPv6 address state
4. The address's local scope

Correct answer: B. Global/remote IPv6 connectivity

Link-local operation is useful for local discovery and next hops. Off-link service needs additional address/path/policy dependencies.

1. No
2. Only if addresses are private
3. Yes, every IPv4 rule covers IPv6
4. Only if TCP port 443 is used

Correct answer: A. No

The active IPv6 path requires appropriate family-specific enforcement. Check actual device policy capabilities and configuration.

1. It makes IPv6 always faster
2. It only blocks decorative messages
3. It can break essential discovery and path feedback
4. IPv6 never uses ICMPv6

Correct answer: C. It can break essential discovery and path feedback

IPv6 relies on important ICMPv6 functions. Use a designed scoped policy rather than treating every message as expendable.

1. All DHCPv4 reservations
2. Ethernet cable labels
3. Whether a neighbor remains reachable for forwarding
4. Public DNS registration

Correct answer: C. Whether a neighbor remains reachable for forwarding

NUD tests neighbor reachability as part of ND operation. It is separate from resolving a hostname.

1. Only if all are loopback
2. Yes
3. Only when it has several NIC cables
4. No, exactly one is allowed

Correct answer: B. Yes

An interface may have link-local and other addresses, including temporary or stable variants. Multiple addresses are not inherently a fault.

1. Wi-Fi airtime
2. Packet forwarding lifetime in hops
3. DNS cache lifetime
4. DHCP pool size

Correct answer: B. Packet forwarding lifetime in hops

Routers reduce hop limit during forwarding. It is analogous in purpose to IPv4 TTL, not DNS TTL.

1. Only the SSID label
2. IPv6 address, neighbor, route, policy, and service state
3. Only IPv4 DHCP options
4. Only the server's A record

Correct answer: B. IPv6 address, neighbor, route, policy, and service state

The failed family has separate dependencies. A working IPv4 test narrows some common factors but does not validate IPv6.

1. The whole IPv6 space
2. All multicast groups
3. One exact IPv6 address
4. A conventional 128-host LAN

Correct answer: C. One exact IPv6 address

All address bits are fixed in a /128. Host routes differ from common LAN prefixes.

1. Treat the prefix as a DNS suffix
2. Assume the address proves Internet access
3. Delete all IPv4 leases
4. Default-router and usable path information separately

Correct answer: D. Default-router and usable path information separately

Address formation and default-router discovery are related but separate fields/dependencies. Verify the actual route and policy.

1. Every IPv6 address is deleted immediately
2. DNS cannot return AAAA
3. The prefix necessarily has zero lifetime
4. The sender is not advertised as a default router by that lifetime value

Correct answer: D. The sender is not advertised as a default router by that lifetime value

Prefix information can still be useful while router lifetime disqualifies that sender as a default router. Inspect each field.

1. 2001:db9:10:20::123
2. 2001:db8:11:20::123
3. 2001:db8:10:20::123
4. 2001:db8:10:21::123

Correct answer: C. 2001:db8:10:20::123

The first four 16-bit groups define /64. Differences after them can remain inside that subnet.

1. The TCP listener port
2. Which local link should carry the exchange
3. The remote Internet route
4. The DNS authoritative zone

Correct answer: B. Which local link should carry the exchange

Interface context disambiguates link-local scope. The result remains a local-link test.

1. The IPv6 path and service/policy for that address
2. Only DHCPv4 lease length
3. Only IPv4 NAT
4. Only whether the A record exists

Correct answer: A. The IPv6 path and service/policy for that address

A correct AAAA answer is name evidence, not a successful IPv6 connection. Test the returned destination family explicitly.

1. Only the browser cache
2. Only public DNS TXT data
3. Only server disk speed
4. Local IPv6 neighbor reachability, VLAN attachment, and control-message path

Correct answer: D. Local IPv6 neighbor reachability, VLAN attachment, and control-message path

The next hop cannot be resolved through the observed exchange. Check the local boundary before remote service hypotheses.

1. Disable all security permanently
2. Investigate actual address ownership and avoid using the conflicting address
3. Use ::1 as the gateway
4. Ignore it because IPv6 is large

Correct answer: B. Investigate actual address ownership and avoid using the conflicting address

Large address space does not make a detected conflict safe. Verify identity and the address-assignment design.

1. Only IPv4 ARP necessarily
2. Local IPv6 neighbor resolution
3. Only DNS caching
4. Only NTP date formatting

Correct answer: B. Local IPv6 neighbor resolution

These control messages support IPv6 local delivery. A route can exist while neighbor resolution fails.

1. Only DHCPv4 ACK
2. Only the A record
3. Default-router discovery/route state and expiry
4. Only the interface's address text

Correct answer: C. Default-router discovery/route state and expiry

Configured address state does not establish usable forwarding. Inspect the active route and router-advertisement context.

1. No, gateways must always be global
2. Only if it becomes IPv4
3. Yes, with the relevant outgoing-link context
4. Only DNS can route link-local

Correct answer: C. Yes, with the relevant outgoing-link context

A next hop is local to its attached link; the final destination can be remote. Do not confuse next-hop scope with destination scope.

1. Always remain preferred forever
2. Automatically become loopback
3. Deprecated rather than immediately invalid
4. Become a DNS alias

Correct answer: C. Deprecated rather than immediately invalid

Preferred and valid lifetimes are distinct. A deprecated address may remain valid for existing use according to host rules.

1. Only the TCP destination port
2. Whether the address remains valid for use under its assignment rules
3. Only AP power
4. Only DNS record TTL

Correct answer: B. Whether the address remains valid for use under its assignment rules

Address validity is not DNS cache validity. Compare the assignment state and current host behavior.

1. Assume DHCPv6 always supplies a default gateway option like DHCPv4
2. Router Advertisements/default-router discovery
3. Only cable color
4. Only DNS PTR data

Correct answer: B. Router Advertisements/default-router discovery

Ordinary IPv6 default-router discovery uses RA, unlike assuming DHCPv4-style gateway delivery. Check current route state.

1. No, every combination is automatically correct
2. Yes, SLAAC disables DNS
3. Yes, only one protocol may exist
4. No; address and other configuration sources can coexist

Correct answer: D. No; address and other configuration sources can coexist

IPv6 configuration can use several mechanisms. Validate effective settings and design rather than assuming coexistence proves a fault.

1. AAAA resolution is impossible
2. IPv4 service works while IPv6 connection fails
3. DHCPv4 stops working
4. Every IPv6 neighbor fails

Correct answer: B. IPv4 service works while IPv6 connection fails

Service binding is family-specific evidence. Network reachability alone cannot create an absent listener.

1. Actual selected source and approved policy scope
2. Only IPv4 lease time
3. Only the DNS name
4. Only fiber reach

Correct answer: A. Actual selected source and approved policy scope

Source-address selection can change which IPv6 address appears in the flow. Identity/policy must match the actual intended behavior.

1. The NIC becomes IPv4-only automatically
2. The host may lose that default-router choice
3. DNS creates another router
4. Every prefix necessarily disappears at the same instant

Correct answer: B. The host may lose that default-router choice

Router and prefix lifetimes are separate. Inspect each state rather than assuming one expiry governs everything.

1. Only the public website's certificate
2. SSID-to-VLAN placement and advertised prefixes
3. Only UDP voice jitter
4. Only the client's screen size

Correct answer: B. SSID-to-VLAN placement and advertised prefixes

An address from an unintended segment is placement evidence. Fix the logical attachment before tuning remote routes blindly.

1. Only the remote DNS zone
2. Only IPv4 NAT translations
3. The on-link next-hop and relevant discovery exchange
4. Only route prefix spelling

Correct answer: C. The on-link next-hop and relevant discovery exchange

Route selection still needs a reachable adjacency. The neighbor failure narrows the local forwarding dependency.

1. No; DNS removed the broadcast
2. Yes; IPv6 ND uses relevant multicast behavior
3. No; all address discovery must broadcast
4. Only if the destination is TCP

Correct answer: B. Yes; IPv6 ND uses relevant multicast behavior

IPv6 does not use IPv4-style broadcast. Interpret the control exchange under ND rules.

1. The remote app has a listener
2. Every IPv6 route is healthy
3. One local ICMPv6 exchange, not the remote service path
4. All TLS certificates are trusted

Correct answer: C. One local ICMPv6 exchange, not the remote service path

Protocol and scope limits still apply in IPv6. Examine the off-link transport/application dependencies.

1. Assume the first packet seen always wins forever
2. Only DNS answer order
3. Actual default-router selection and current route/neighbor state
4. Only the largest address string

Correct answer: C. Actual default-router selection and current route/neighbor state

Hosts can have multiple router choices. Read effective state and design rather than inventing a universal selection rule.

1. Observing the exchange
2. Calling STALE alone proof of an outage
3. Recording the state transition
4. Comparing current reachability

Correct answer: B. Calling STALE alone proof of an outage

Cache states represent protocol operation, not always failure. Use subsequent packet behavior to evaluate health.

1. An IPv4 /24 gaining hosts
2. Size-dependent remote transfer failure
3. A DNS name becoming shorter
4. A Wi-Fi SSID disappearing necessarily

Correct answer: B. Size-dependent remote transfer failure

Path MTU behavior depends on necessary feedback and endpoint handling. Handshake success may not prove larger payload delivery.

1. Only DNS decides forwarding
2. Global addresses never route
3. Every global address is multicast
4. Routing, neighbor state, policy, and remote service still matter

Correct answer: D. Routing, neighbor state, policy, and remote service still matter

An address is configuration evidence. Verify the whole required path and service using current observations.

1. DNS necessarily returned the wrong address
2. The prefix must be /24
3. Address formation succeeded without an advertised usable default router
4. Local peers prove global routing

Correct answer: C. Address formation succeeded without an advertised usable default router

The RA fields serve different roles. A usable local address does not supply a default route when the router lifetime is zero.

1. A=1 means DNS only
2. Prefix text always overrides all flags
3. L=0 disables all IPv6 addressing
4. Autonomous address formation and on-link indication are distinct flags

Correct answer: D. Autonomous address formation and on-link indication are distinct flags

The autonomous and on-link flags carry separate information. Inspect the actual on-link/route state rather than importing one flag's meaning into the other.

1. A DHCPv4 gateway option copied blindly
2. Every DNS record
3. The required RA/default-router discovery path
4. An IPv4 ARP entry

Correct answer: C. The required RA/default-router discovery path

DHCPv6 address allocation is not a substitute for ordinary RA-based default-router discovery. Validate the host's route after correction.

1. DNS name absence
2. IPv6 return routing for the client prefix
3. Local neighbor resolution failure already disproved for the test
4. DHCPv4 exhaustion

Correct answer: B. IPv6 return routing for the client prefix

The request arrives, while the return-path evidence identifies a missing dependency. Inspect replies rather than repeating local discovery tests.

1. Authorized router identity and a supported first-hop protection policy
2. Only DNS TTL
3. Only server disk capacity
4. Only the IPv4 DHCP scope

Correct answer: A. Authorized router identity and a supported first-hop protection policy

RA can affect host router selection. Confirm authorized sources and scoped protection without blocking essential control traffic indiscriminately.

1. The IPv6 boundary needs equivalent intended policy verification
2. VLAN tags are impossible on IPv6
3. DNS automatically bypasses all firewalls
4. The IPv4 test was never valid

Correct answer: A. The IPv6 boundary needs equivalent intended policy verification

Different families can have separate enforcement. Test and correct the actual permitted IPv6 path.

1. Yes; all sessions must end at once
2. Yes; deprecated always means invalid immediately
3. No; preferred and valid lifetimes support distinct address states
4. No; lifetime fields never matter

Correct answer: C. No; preferred and valid lifetimes support distinct address states

Deprecation affects preferred use without necessarily ending all existing valid use. Examine actual host policy and lifetimes.

1. That no solicitation was sent on the client's actual link
2. Capture placement matters
3. VLAN boundaries matter
4. Local discovery is link-scoped

Correct answer: A. That no solicitation was sent on the client's actual link

ND has local-link scope. An observation point outside that link cannot directly inventory every local control message.

1. Only the largest hop limit
2. The associated interface/zone and route context
3. Only the DNS suffix
4. Only DHCPv4 lease time

Correct answer: B. The associated interface/zone and route context

Link-local addresses can recur on different links. The forwarding adjacency must include the appropriate local interface.

1. Disable all network security
2. Change the IPv4 subnet blindly
3. Test every returned intended endpoint/family and its service binding
4. Assume all DNS is wrong

Correct answer: C. Test every returned intended endpoint/family and its service binding

Multiple returned destinations can produce mixed outcomes. Isolate the failing member rather than generalizing across families.

1. Only the site's public A record
2. Only Wi-Fi band selection
3. The cloned assignment/identity scheme and actual link ownership
4. Only WAN throughput

Correct answer: C. The cloned assignment/identity scheme and actual link ownership

Cloned static configuration can defeat intended uniqueness. DAD evidence needs ownership checks and coordinated assignment repair.

1. Only server password
2. Only TCP receive window
3. The route/prefix flags and intended on-link classification
4. Only DNS cache length

Correct answer: C. The route/prefix flags and intended on-link classification

An incorrect on-link assumption directs neighbor discovery toward the destination itself. Verify the classification before blaming the gateway.

1. Only the SSID name
2. Only IPv4 ARP
3. Path MTU discovery/feedback and endpoint packet sizing
4. Only DNS MX records

Correct answer: C. Path MTU discovery/feedback and endpoint packet sizing

IPv6 routers do not perform IPv4-style transit fragmentation. Required size feedback and endpoint handling matter for larger packets.

1. Local addresses persist while a default-router choice disappears
2. DNS creates an implicit default
3. Every address must expire simultaneously
4. The NIC cannot send any local traffic

Correct answer: A. Local addresses persist while a default-router choice disappears

Separate lifetimes can yield separate operational outcomes. Inspect router-list and address state independently.

1. The default entry proves delivery
2. Only DNS can fix neighbor state
3. The server must be offline
4. The local next-hop adjacency is unusable

Correct answer: D. The local next-hop adjacency is unusable

A selected route must resolve to a usable local neighbor. Default-router presence is not end-to-end or adjacency proof.

1. Actual source selection and an approved identity/address scope
2. Only IPv4 NAT
3. Only the stable address's existence
4. Only the hostname text

Correct answer: A. Actual source selection and an approved identity/address scope

The packet may not use the address named in the rule. Adjust intentionally rather than admitting an entire unrelated prefix by default.

1. DNS chooses specificity
2. IPv6 cannot have host routes
3. /64 is always longer
4. The matching /128 fixes more bits and is the more specific route

Correct answer: D. The matching /128 fixes more bits and is the more specific route

Prefix length counts fixed bits in IPv6 too. A matching host route is more specific than the surrounding LAN prefix.

1. Unexpected control traffic was observed; its actual client effect still needs evidence
2. Every RA is malicious
3. A total outage is proven
4. The rogue source is definitely the gateway used

Correct answer: A. Unexpected control traffic was observed; its actual client effect still needs evidence

Observation of a message is distinct from proof it was accepted or caused a symptom. Verify source authorization and host state.

1. Inspecting selected source
2. Checking DAD state
3. Distinguishing valid/preferred state
4. Using tentative presence as proof that address is ready for normal service

Correct answer: D. Using tentative presence as proof that address is ready for normal service

Address lifecycle state matters. An address shown in output may not yet be usable normally.

1. Link-local addresses become globally routed
2. DNS converts gateway scope
3. The server must share the gateway address
4. The next hop is on the local link; the packet's final destination is separate

Correct answer: D. The next hop is on the local link; the packet's final destination is separate

Next-hop identity and final destination have different scopes. The router forwards the packet beyond that first local delivery.

1. Required authorized RA/ND behavior still works while unauthorized advertisements are constrained
2. Only a successful IPv4 ping
3. Blocking all ICMPv6
4. Only a rule name containing Guard

Correct answer: A. Required authorized RA/ND behavior still works while unauthorized advertisements are constrained

First-hop protection must preserve essential approved control exchanges. Validate positive and negative behavior on the supported platform.

1. Only WAN bandwidth
2. Only the old prefix's spelling
3. Current VLAN attachment and router/prefix discovery on the new link
4. Only IPv4 DNS

Correct answer: C. Current VLAN attachment and router/prefix discovery on the new link

Mobility changed the relevant link. Validate current network placement and fresh control information, not stale address state.

1. Every IPv6 packet is filtered
2. IPv6 network exchange works for the ping; the desired family-specific service is absent
3. DNS cannot resolve IPv6
4. The default router is necessarily missing

Correct answer: B. IPv6 network exchange works for the ping; the desired family-specific service is absent

Protocol reachability and application binding are distinct. The listener evidence explains why ping cannot guarantee HTTPS.

1. The approved local ND control path and policy
2. The hostname only
3. The IPv4 lease only
4. Every application account

Correct answer: A. The approved local ND control path and policy

Address and route text do not replace neighbor resolution. Check the missing local exchange and scope the control correction.

1. The combined changes restored tested service without isolating one cause
2. RA flags alone were proven wrong
3. Firewall policy was certainly irrelevant
4. Client state could not matter

Correct answer: A. The combined changes restored tested service without isolating one cause

Different changed dependencies may all affect the path. Document the final design and verify with focused follow-up tests.