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Read each scenario carefully and choose your answer before revealing the explanation. Then check why your choice was right or wrong. Repeat until the reasoning feels automatic.

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300-410 · topic practice

DHCP (IPv4 and IPv6) practice questions

Practise 300-410 DHCP questions covering DORA flow, scopes, excluded addresses, default gateway options, helper addresses, and troubleshooting clients that receive APIPA or cannot get an IP address.

Courseiva uses original exam-style practice questions designed for learning and revision. The goal is to understand the concepts, recognise exam patterns, and improve through explanations — not memorise copied exam dumps.

Reviewed byJohnson Ajibi· MSc IT Security

20 questionsDomain: DHCP (IPv4 and IPv6)

Practice 10 questions Browse domain →

What the exam tests

What to know about DHCP (IPv4 and IPv6)

IPv6 questions usually test address types (link-local, global unicast, ULA), autoconfiguration (SLAAC), Neighbor Discovery Protocol and the differences from IPv4.

IPv6 address types and their scopes (link-local, global unicast, multicast, ULA).

SLAAC vs DHCPv6 vs stateful assignment.

Neighbor Discovery Protocol replacing ARP.

IPv6 routing differences and dual-stack coexistence.

Why learners struggle

Why DHCP (IPv4 and IPv6) questions are commonly missed

DHCP questions are missed when learners overlook the relay agent requirement for cross-subnet assignments, or assume that because a DHCP server exists, a client will always get an address. Routing, relay, scope, and exclusion details all affect the outcome.

·DHCP relay required — clients on a different subnet cannot broadcast to a remote DHCP server without a helper address
·Excluded addresses — addresses in an excluded range are never offered, even if they are in the scope
·Default gateway option — must match the client subnet, not the server's subnet
·APIPA address (169.254.x.x) — indicates DHCP discovery failed, not a server response
·DORA flow — Discovery, Offer, Request, Acknowledgement; missing any step breaks assignment
·Scope exhaustion — a full scope returns no addresses even when the server is reachable

Watch out for

Common DHCP (IPv4 and IPv6) exam traps

▸Link-local addresses are not routable beyond the local link.
▸SLAAC uses EUI-64 or random interface IDs — not a DHCP server.
▸NDP uses ICMPv6, not ARP.
▸An IPv6 prefix is /64 for most host subnets, not /24.

Practice set

DHCP (IPv4 and IPv6) questions

20 questions · select your answer, then reveal the explanation

Question 1mediummultiple choice

Open the full VLAN trunking answer →

A network engineer is troubleshooting a DHCPv4 issue on a Cisco router configured as a DHCP server. Clients on VLAN 10 are unable to obtain IP addresses. The engineer verifies that the DHCP pool is correctly configured and that the router interface facing the clients has 'ip helper-address 192.168.1.1' pointing to the DHCP server. However, the DHCP server is on a different subnet and the router's interface is in a VRF. The DHCP DISCOVER messages are not reaching the server. What is the most likely cause?

Trap 1: The DHCP pool is missing the 'default-router' command.

Incorrect because the DHCP pool configuration is verified correct, and missing default-router would not prevent DISCOVER messages from reaching the server.

Trap 2: The router needs the 'ip dhcp relay information option' command to…

Incorrect because Option 82 is not required for basic DHCP relay; it is used for security and policy, not for basic forwarding.

Trap 3: The DHCP server is not configured with a scope for the client…

Incorrect because the issue is that DISCOVER messages never reach the server, so the server's scope configuration is irrelevant at this point.

Study all DHCP (IPv4 and IPv6) common traps →

A
The DHCP pool is missing the 'default-router' command.
Why wrong: Incorrect because the DHCP pool configuration is verified correct, and missing default-router would not prevent DISCOVER messages from reaching the server.
B
The router needs the 'ip dhcp relay information option' command to insert Option 82.
Why wrong: Incorrect because Option 82 is not required for basic DHCP relay; it is used for security and policy, not for basic forwarding.
C
The 'ip helper-address' command must be configured under the interface with the VRF name using 'ip helper-address vrf <vrf-name> <server-ip>'.
Correct because when the interface is in a VRF, the helper address must specify the VRF to ensure the DHCP broadcast is forwarded into the correct routing table.
D
The DHCP server is not configured with a scope for the client subnet.
Why wrong: Incorrect because the issue is that DISCOVER messages never reach the server, so the server's scope configuration is irrelevant at this point.

Full breakdown with real-world context →

Question 2mediummultiple choice

Read the full DHCP explanation →

An engineer is troubleshooting an IPv6 deployment where hosts on a subnet are not receiving IPv6 addresses via SLAAC. The router is configured with 'ipv6 unicast-routing' and the interface has 'ipv6 address 2001:db8:1::1/64' and 'ipv6 nd other-config-flag'. The hosts are sending Router Solicitations but receive no Router Advertisements. What is the root cause?

Trap 1: The interface is missing the 'ipv6 enable' command.

Incorrect because 'ipv6 enable' is not required if an IPv6 address is already configured; the address itself enables IPv6 on the interface.

Trap 2: The 'ipv6 nd prefix' command is missing for the subnet.

Incorrect because by default, the router advertises the prefix configured on the interface; a specific 'ipv6 nd prefix' command is only needed to modify advertisement parameters.

Trap 3: The hosts are using DHCPv6 instead of SLAAC.

Incorrect because the issue is that no RAs are received, which is required for both SLAAC and DHCPv6 stateless; the symptom points to RA suppression.

Study all DHCP (IPv4 and IPv6) common traps →

A
The interface is missing the 'ipv6 enable' command.
Why wrong: Incorrect because 'ipv6 enable' is not required if an IPv6 address is already configured; the address itself enables IPv6 on the interface.
B
The 'ipv6 nd ra suppress' command is configured on the interface.
Correct because this command suppresses Router Advertisements, preventing hosts from receiving RAs even though the interface has an IPv6 address.
C
The 'ipv6 nd prefix' command is missing for the subnet.
Why wrong: Incorrect because by default, the router advertises the prefix configured on the interface; a specific 'ipv6 nd prefix' command is only needed to modify advertisement parameters.
D
The hosts are using DHCPv6 instead of SLAAC.
Why wrong: Incorrect because the issue is that no RAs are received, which is required for both SLAAC and DHCPv6 stateless; the symptom points to RA suppression.

Full breakdown with real-world context →

Question 3hardmultiple choice

Read the full DHCP explanation →

A network engineer is troubleshooting a DHCPv4 relay scenario where clients on subnet 10.1.1.0/24 are unable to obtain IP addresses from a DHCP server at 192.168.1.10. The router interface Gi0/0 (10.1.1.1/24) has 'ip helper-address 192.168.1.10' configured. The engineer captures packets and sees DHCP DISCOVER messages sourced from 10.1.1.1 being sent to 192.168.1.10, but no replies are seen. The server is reachable via ping from the router. What is the most likely cause?

Trap 1: The DHCP server does not have a route to 10.1.1.0/24.

Incorrect because the server is reachable via ping from the router, indicating routing is functional; the issue is at the application layer.

Trap 2: The 'ip helper-address' command should be configured on the…

Incorrect because the helper address must be on the interface facing the clients to intercept their DHCP broadcasts.

Trap 3: The router needs the 'ip dhcp relay information option' command.

Incorrect because Option 82 is optional and not required for basic relay; its absence does not prevent the server from receiving the DISCOVER.

Study all DHCP (IPv4 and IPv6) common traps →

A
The DHCP server does not have a route to 10.1.1.0/24.
Why wrong: Incorrect because the server is reachable via ping from the router, indicating routing is functional; the issue is at the application layer.
B
The DHCP server is not configured with a scope for subnet 10.1.1.0/24.
Correct because if the server has no scope for the client subnet, it will ignore the DISCOVER message and not send any reply, even though the relayed packet reaches the server.
C
The 'ip helper-address' command should be configured on the server-facing interface, not the client-facing interface.
Why wrong: Incorrect because the helper address must be on the interface facing the clients to intercept their DHCP broadcasts.
D
The router needs the 'ip dhcp relay information option' command.
Why wrong: Incorrect because Option 82 is optional and not required for basic relay; its absence does not prevent the server from receiving the DISCOVER.

Full breakdown with real-world context →

Question 4hardmultiple choice

Read the full DHCP explanation →

An engineer is troubleshooting a DHCPv6 stateful (DHCPv6) deployment. The router is configured as a DHCPv6 server with a pool for prefix 2001:db8:2::/64. Clients on the LAN are configured to use DHCPv6, but they are not receiving IPv6 addresses. The router interface has 'ipv6 address 2001:db8:2::1/64' and 'ipv6 dhcp server DHCP_POOL'. The engineer sees that the clients are sending SOLICIT messages, but the router sends no REPLY. What is the issue?

Trap 1: The interface is missing the 'ipv6 nd managed-config-flag' command.

Incorrect because clients are already sending SOLICIT messages, indicating they are using DHCPv6; the M flag is not required for the server to respond to SOLICITs.

Trap 2: The router needs the 'ipv6 dhcp relay' command on the interface.

Incorrect because the router is acting as a server, not a relay; relay is used when the server is on a different subnet.

Trap 3: The 'ipv6 unicast-routing' command is missing globally.

Incorrect because IPv6 unicast routing is not required for the DHCPv6 server to function; it only affects routing protocol operation.

Study all DHCP (IPv4 and IPv6) common traps →

A
The interface is missing the 'ipv6 nd managed-config-flag' command.
Why wrong: Incorrect because clients are already sending SOLICIT messages, indicating they are using DHCPv6; the M flag is not required for the server to respond to SOLICITs.
B
The DHCPv6 pool is missing the 'address prefix 2001:db8:2::/64' command.
Correct because without an address prefix in the pool, the DHCPv6 server has no addresses to assign and will not send a REPLY to SOLICIT messages.
C
The router needs the 'ipv6 dhcp relay' command on the interface.
Why wrong: Incorrect because the router is acting as a server, not a relay; relay is used when the server is on a different subnet.
D
The 'ipv6 unicast-routing' command is missing globally.
Why wrong: Incorrect because IPv6 unicast routing is not required for the DHCPv6 server to function; it only affects routing protocol operation.

Full breakdown with real-world context →

Question 5easymultiple choice

Read the full DHCP explanation →

A network engineer is troubleshooting a DHCPv4 issue where clients on a subnet are getting IP addresses from the correct pool, but they cannot reach the default gateway. The router is configured as a DHCP server with pool 'POOL' that includes 'default-router 192.168.1.1'. The router's interface IP is 192.168.1.1/24. Clients receive the address and default gateway, but pings to 192.168.1.1 fail. What is the most likely cause?

Trap 1: The DHCP pool has the wrong subnet mask.

Incorrect because the subnet mask affects the client's network prefix, but the default gateway IP is still reachable if it's on the same subnet; the issue is that the gateway itself is unreachable.

Trap 2: The 'ip helper-address' command is interfering with DHCP.

Incorrect because the router is the DHCP server, not a relay; helper-address is not used in this scenario.

Trap 3: The clients have a static ARP entry for the gateway.

Incorrect because static ARP would not cause pings to fail; it would actually help if the ARP entry is correct.

Study all DHCP (IPv4 and IPv6) common traps →

A
The DHCP pool has the wrong subnet mask.
Why wrong: Incorrect because the subnet mask affects the client's network prefix, but the default gateway IP is still reachable if it's on the same subnet; the issue is that the gateway itself is unreachable.
B
The router interface Gi0/0 is administratively down.
Correct because if the interface is down, the router cannot respond to ARP requests or pings from clients, even though DHCP assignments are still possible (the server process runs independently).
C
The 'ip helper-address' command is interfering with DHCP.
Why wrong: Incorrect because the router is the DHCP server, not a relay; helper-address is not used in this scenario.
D
The clients have a static ARP entry for the gateway.
Why wrong: Incorrect because static ARP would not cause pings to fail; it would actually help if the ARP entry is correct.

Full breakdown with real-world context →

Question 6mediummultiple choice

Read the full DHCP explanation →

An engineer is troubleshooting a DHCPv4 issue where a Cisco router acting as a DHCP client on interface Gi0/0 is not receiving an IP address from an ISP modem. The router has 'ip address dhcp' on the interface. The engineer sees that the interface is up/up, but no IP address is assigned. Debug shows that the router is sending DHCP DISCOVER messages but receives no OFFER. The ISP modem is known to work with other devices. What is the most likely cause?

Trap 1: The router needs the 'ip dhcp client broadcast-flag' command.

Incorrect because the broadcast flag is used to request a broadcast reply; it does not affect the DISCOVER being ignored.

Trap 2: The router's interface is in a VRF, and the DHCP client needs VRF…

Incorrect because the interface is not mentioned to be in a VRF; this is a standard DHCP client scenario.

Trap 3: The ISP modem requires DHCP Option 82 to be present.

Incorrect because Option 82 is typically added by relay agents, not clients; modems rarely require it.

Study all DHCP (IPv4 and IPv6) common traps →

A
The router needs the 'ip dhcp client broadcast-flag' command.
Why wrong: Incorrect because the broadcast flag is used to request a broadcast reply; it does not affect the DISCOVER being ignored.
B
The router is sending the client identifier as the MAC address in a non-standard format; the modem expects the client identifier to be the MAC address only.
Correct because Cisco routers by default send the client identifier as the MAC address with a type byte (0x01), while some modems expect only the MAC address; configuring 'ip dhcp client client-id' with the correct format resolves the issue.
C
The router's interface is in a VRF, and the DHCP client needs VRF awareness.
Why wrong: Incorrect because the interface is not mentioned to be in a VRF; this is a standard DHCP client scenario.
D
The ISP modem requires DHCP Option 82 to be present.
Why wrong: Incorrect because Option 82 is typically added by relay agents, not clients; modems rarely require it.

Full breakdown with real-world context →

Question 7hardmultiple choice

Open the full VLAN trunking answer →

A network engineer is troubleshooting a DHCPv4 issue where a router configured as a DHCP server is not assigning addresses from a pool to clients on a specific VLAN. The pool is configured with 'network 10.1.1.0 255.255.255.0' and 'default-router 10.1.1.1'. The router's interface Gi0/0.10 (subinterface) has encapsulation dot1Q 10 and IP 10.1.1.1/24. Clients send DISCOVER messages, but the router does not respond. The engineer notices that the router has multiple DHCP pools configured. What is the most likely cause?

Trap 1: The subinterface is missing the 'ip helper-address' command.

Incorrect because the router is the DHCP server, so helper-address is not needed; the server responds directly to DISCOVER messages on the same subnet.

Trap 2: The 'ip dhcp server' command is missing globally.

Incorrect because the DHCP server process is enabled by default when a pool is configured; no global command is needed.

Trap 3: The encapsulation dot1Q 10 is misconfigured, causing the router to…

Incorrect because if the subinterface were misconfigured, it would not be up/up; the engineer would see the interface status as down.

Study all DHCP (IPv4 and IPv6) common traps →

A
The DHCP pool is configured under a VRF, but the interface is not in that VRF.
Correct because if the pool is defined with 'vrf <name>', it will only respond to DHCP requests on interfaces belonging to that VRF; the subinterface is not in any VRF, so the pool is ignored.
B
The subinterface is missing the 'ip helper-address' command.
Why wrong: Incorrect because the router is the DHCP server, so helper-address is not needed; the server responds directly to DISCOVER messages on the same subnet.
C
The 'ip dhcp server' command is missing globally.
Why wrong: Incorrect because the DHCP server process is enabled by default when a pool is configured; no global command is needed.
D
The encapsulation dot1Q 10 is misconfigured, causing the router to not receive broadcasts.
Why wrong: Incorrect because if the subinterface were misconfigured, it would not be up/up; the engineer would see the interface status as down.

Full breakdown with real-world context →

Question 8hardmultiple choice

Read the full DHCP explanation →

An engineer is troubleshooting a DHCPv6 prefix delegation scenario. The router (R1) is a DHCPv6 client on its WAN interface and is supposed to receive a /48 prefix from the ISP's DHCPv6 server to delegate to LAN interfaces. The WAN interface is configured with 'ipv6 address dhcp' and 'ipv6 dhcp client pd ISP-PREFIX'. The LAN interfaces have 'ipv6 address ISP-PREFIX 0:0:0:1::/64 eui-64'. The engineer sees that the WAN interface gets a global IPv6 address, but the LAN interfaces do not get any IPv6 address. What is the most likely cause?

Trap 1: The LAN interfaces are missing the 'ipv6 enable' command.

Incorrect because 'ipv6 address ... eui-64' enables IPv6 on the interface; 'ipv6 enable' is not required.

Trap 2: The 'ipv6 dhcp client pd' command should be 'ipv6 dhcp client pd…

Incorrect because the 'hint' option is optional and does not prevent delegation; the server may still delegate a different prefix.

Trap 3: The WAN interface needs the 'ipv6 nd other-config-flag' command.

Incorrect because the 'other-config-flag' is for LAN interfaces to indicate additional information; it is not related to prefix delegation on the WAN.

Study all DHCP (IPv4 and IPv6) common traps →

A
The LAN interfaces are missing the 'ipv6 enable' command.
Why wrong: Incorrect because 'ipv6 address ... eui-64' enables IPv6 on the interface; 'ipv6 enable' is not required.
B
The ISP's DHCPv6 server is not configured to delegate a prefix.
Correct because if the server does not delegate a prefix, the client's 'ipv6 dhcp client pd' request will fail, and the LAN interfaces will not receive any addresses from the delegated prefix.
C
The 'ipv6 dhcp client pd' command should be 'ipv6 dhcp client pd ISP-PREFIX hint ::/48'.
Why wrong: Incorrect because the 'hint' option is optional and does not prevent delegation; the server may still delegate a different prefix.
D
The WAN interface needs the 'ipv6 nd other-config-flag' command.
Why wrong: Incorrect because the 'other-config-flag' is for LAN interfaces to indicate additional information; it is not related to prefix delegation on the WAN.

Full breakdown with real-world context →

Question 9mediummultiple choice

Read the full DHCP explanation →

A network engineer is troubleshooting a DHCPv4 issue where a router configured as a DHCP server is not assigning addresses to clients on a subnet that is reachable via a different router (relay). The relay router (R2) has 'ip helper-address 10.1.1.1' on its client-facing interface, and the DHCP server is at 10.1.1.1 (R1). The engineer sees that R2 is sending DHCP DISCOVER messages with giaddr set to the client-facing interface IP, but R1 is not responding. R1 has a DHCP pool for the client subnet. The engineer pings 10.1.1.1 from R2 successfully. What is the most likely cause?

Trap 1: The relay agent R2 is missing the 'ip dhcp relay information…

Incorrect because Option 82 is not required for basic relay; its absence does not prevent the server from responding.

Trap 2: The DHCP pool on R1 is missing the 'default-router' command.

Incorrect because missing default-router would still allow the server to send an OFFER with an IP address; the client would just not have a gateway.

Trap 3: The 'ip helper-address' on R2 should point to the server's loopback…

Incorrect because the helper address can be any IP reachable on the server; the interface IP is fine.

Study all DHCP (IPv4 and IPv6) common traps →

A
The DHCP server does not have a route to the client subnet (the giaddr subnet).
Correct because the server sends the OFFER to the giaddr IP, which is on a different subnet; without a route back, the OFFER is lost.
B
The relay agent R2 is missing the 'ip dhcp relay information option' command.
Why wrong: Incorrect because Option 82 is not required for basic relay; its absence does not prevent the server from responding.
C
The DHCP pool on R1 is missing the 'default-router' command.
Why wrong: Incorrect because missing default-router would still allow the server to send an OFFER with an IP address; the client would just not have a gateway.
D
The 'ip helper-address' on R2 should point to the server's loopback address, not the interface IP.
Why wrong: Incorrect because the helper address can be any IP reachable on the server; the interface IP is fine.

Full breakdown with real-world context →

Question 10mediummultiple choice

Read the full DHCP explanation →

A network engineer runs the following command on Router R1:

R1# show ip dhcp binding

Bindings from all pools not associated with VRF:

IP address       Client-ID/              Lease expiration        Type

Hardware address/ User name

192.168.1.10     0063.6973.636f.2e30.    Mar 01 2020 12:00 AM    Automatic
                 3030.3030.2e30.3030
                 312e.3130.3030.2e30
                 3030.312d.4574.682d

302f.31

192.168.1.11     0063.6973.636f.2e30.    Mar 01 2020 12:00 AM    Automatic
                 3030.3030.2e30.3030
                 312e.3130.3030.2e30
                 3030.312d.4574.682d

302f.31

Based on this output, which statement is correct?

Trap 1: The DHCP server is functioning correctly with two unique bindings.

The client-IDs are identical, so they are not unique.

Trap 2: The DHCP server has run out of addresses in the pool.

There is no indication of pool exhaustion; only two bindings are shown.

Trap 3: The DHCP server is not assigning addresses because the lease time…

Lease expiration is shown, but it does not indicate a lease time of 0.

Study all DHCP (IPv4 and IPv6) common traps →

A
The DHCP server is functioning correctly with two unique bindings.
Why wrong: The client-IDs are identical, so they are not unique.
B
The DHCP server has a duplicate client-id issue, likely caused by two clients using the same client identifier.
The hex client-id is identical for both bindings, indicating a duplicate.
C
The DHCP server has run out of addresses in the pool.
Why wrong: There is no indication of pool exhaustion; only two bindings are shown.
D
The DHCP server is not assigning addresses because the lease time is set to 0.
Why wrong: Lease expiration is shown, but it does not indicate a lease time of 0.

Full breakdown with real-world context →

Question 11mediummultiple choice

Read the full DHCP explanation →

A network engineer runs the following command on Router R1:

R1# show ip dhcp conflict
IP address       Detection method     Detection time        VRF
192.168.1.20     Ping                 Mar 01 2020 01:00 AM  
192.168.1.21     Gratuitous ARP       Mar 01 2020 01:05 AM

Based on this output, what is the problem?

Trap 1: The DHCP server is working normally; conflicts are automatically…

Conflicts are logged and prevent address assignment until cleared.

Trap 2: The DHCP server is not responding to client requests.

The output shows conflicts, not a lack of responses.

Trap 3: The DHCP pool is misconfigured with overlapping subnets.

Overlapping pools would not cause conflicts; conflicts are from external devices.

Study all DHCP (IPv4 and IPv6) common traps →

A
The DHCP server is working normally; conflicts are automatically resolved.
Why wrong: Conflicts are logged and prevent address assignment until cleared.
B
The DHCP server has detected IP address conflicts, meaning another device on the network is using the same IP addresses.
Conflicts indicate duplicate IP usage on the network.
C
The DHCP server is not responding to client requests.
Why wrong: The output shows conflicts, not a lack of responses.
D
The DHCP pool is misconfigured with overlapping subnets.
Why wrong: Overlapping pools would not cause conflicts; conflicts are from external devices.

Full breakdown with real-world context →

Question 12mediummultiple choice

Read the full DHCP explanation →

A network engineer runs the following command on Router R1:

R1# show ipv6 dhcp binding

Client: FE80::A8BB:CCFF:FE01:0200 DUID: 00030001AABBCC010200

Username: unassigned

IA NA: IA ID 0x00010001, T1 302400, T2 483840 Address: 2001:DB8:1::1000 Preferred lifetime 604800, valid lifetime 2592000 Expires at Mar 08 2020 12:00 AM (2592000 seconds) Client: FE80::A8BB:CCFF:FE01:0300 DUID: 00030001AABBCC010300

Username: unassigned

IA NA: IA ID 0x00010001, T1 302400, T2 483840 Address: 2001:DB8:1::1001 Preferred lifetime 604800, valid lifetime 2592000 Expires at Mar 08 2020 12:00 AM (2592000 seconds)

Based on this output, which statement is correct?

Trap 1: The DHCPv6 server has assigned duplicate addresses to the clients.

The addresses are different (::1000 and ::1001).

Trap 2: The DHCPv6 server is not using a pool; addresses are statically…

The output shows dynamic bindings with lifetimes.

Trap 3: The DHCPv6 server has a DUID conflict.

The DUIDs are different for each client.

Study all DHCP (IPv4 and IPv6) common traps →

A
The DHCPv6 server has assigned duplicate addresses to the clients.
Why wrong: The addresses are different (::1000 and ::1001).
B
The DHCPv6 server is functioning correctly with two active bindings.
Both clients have unique bindings and valid lifetimes.
C
The DHCPv6 server is not using a pool; addresses are statically assigned.
Why wrong: The output shows dynamic bindings with lifetimes.
D
The DHCPv6 server has a DUID conflict.
Why wrong: The DUIDs are different for each client.

Full breakdown with real-world context →

Question 13hardmultiple choice

Read the full DHCP explanation →

A network engineer runs the following command on Router R1:

R1# show ip dhcp server statistics

Memory usage 26140 Address conflicts 0

Pool statistics

Pool IP addresses Requests Offers Acks Naks Declines Releases POOL1 10-20 50 45 40 5 2 3

Based on this output, which statement is correct?

Trap 1: The DHCP server is operating without any issues.

There are Naks and Declines, indicating problems.

Trap 2: The DHCP server has a memory problem.

Memory usage is shown but not indicated as a problem.

Trap 3: The DHCP server has no address conflicts.

Address conflicts are 0, but declines indicate conflicts detected by clients.

Study all DHCP (IPv4 and IPv6) common traps →

A
The DHCP server is operating without any issues.
Why wrong: There are Naks and Declines, indicating problems.
B
The DHCP server is rejecting requests (Naks) and clients are declining offers, indicating possible pool exhaustion or address conflicts.
Naks and Declines are signs of issues.
C
The DHCP server has a memory problem.
Why wrong: Memory usage is shown but not indicated as a problem.
D
The DHCP server has no address conflicts.
Why wrong: Address conflicts are 0, but declines indicate conflicts detected by clients.

Full breakdown with real-world context →

Question 14mediummultiple choice

Read the full DHCP explanation →

A network engineer runs the following command on Router R1:

R1# show ip dhcp pool POOL1

Pool POOL1 : Utilization mark (high/low) : 100 / 0 Subnet size (first/next) : 0 / 0 Total addresses : 10 Leased addresses : 10 Pending event : none 1 subnet is currently in the pool : Current index IP address range Leased addresses

192.168.1.11         192.168.1.10    - 192.168.1.19       10

Based on this output, which statement is correct?

Trap 1: The DHCP pool has available addresses for new clients.

All 10 addresses are leased.

Trap 2: The DHCP pool is configured with a /24 subnet.

The range shows only 10 addresses.

Trap 3: The DHCP server has a pending event causing address allocation to…

Pending event is 'none'.

Study all DHCP (IPv4 and IPv6) common traps →

A
The DHCP pool has available addresses for new clients.
Why wrong: All 10 addresses are leased.
B
The DHCP pool is fully utilized; no more addresses are available.
Leased addresses equal total addresses.
C
The DHCP pool is configured with a /24 subnet.
Why wrong: The range shows only 10 addresses.
D
The DHCP server has a pending event causing address allocation to fail.
Why wrong: Pending event is 'none'.

Full breakdown with real-world context →

Question 15mediummultiple choice

Open the full VLAN trunking answer →

A network engineer runs the following command on Router R1:

R1# show ip dhcp snooping binding

MacAddress IpAddress Lease(sec) Type VLAN Interface AA:BB:CC:01:02:03 192.168.1.10 86400 dhcp-snooping 10 GigabitEthernet0/1 AA:BB:CC:01:02:04 192.168.1.11 86400 dhcp-snooping 10 GigabitEthernet0/1 AA:BB:CC:01:02:05 192.168.1.12 86400 dhcp-snooping 10 GigabitEthernet0/2

Based on this output, which statement is correct?

Trap 1: DHCP snooping has detected a rogue DHCP server on…

No indication of a rogue server.

Trap 2: DHCP snooping is not functioning because the bindings are not…

Bindings are recorded; trust is per interface.

Trap 3: DHCP snooping has a conflict because two clients are on the same…

Multiple clients on the same interface is normal.

Study all DHCP (IPv4 and IPv6) common traps →

A
DHCP snooping is enabled and has recorded bindings for three clients.
The table shows valid bindings.
B
DHCP snooping has detected a rogue DHCP server on GigabitEthernet0/1.
Why wrong: No indication of a rogue server.
C
DHCP snooping is not functioning because the bindings are not trusted.
Why wrong: Bindings are recorded; trust is per interface.
D
DHCP snooping has a conflict because two clients are on the same interface.
Why wrong: Multiple clients on the same interface is normal.

Full breakdown with real-world context →

Question 16easymultiple choice

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A network engineer runs the following command on Router R1:

R1# show ipv6 dhcp interface GigabitEthernet0/1

GigabitEthernet0/1 is in server mode Using pool: POOL6 Preference value: 0 Hint from client: ignored Rapid-Commit: disabled

Based on this output, which statement is correct?

Trap 1: The interface is configured as a DHCPv6 client.

It is in server mode.

Trap 2: The interface is using rapid-commit for faster address assignment.

Rapid-commit is disabled.

Trap 3: The interface is in DHCPv6 relay mode.

It is in server mode, not relay.

Study all DHCP (IPv4 and IPv6) common traps →

A
The interface is configured as a DHCPv6 client.
Why wrong: It is in server mode.
B
The interface is configured as a DHCPv6 server using pool POOL6.
Server mode with pool specified.
C
The interface is using rapid-commit for faster address assignment.
Why wrong: Rapid-commit is disabled.
D
The interface is in DHCPv6 relay mode.
Why wrong: It is in server mode, not relay.

Full breakdown with real-world context →

Question 17easymultiple choice

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A network engineer runs the following command on Router R1:

R1# show ip dhcp relay information trusted
Interface                Trusted

GigabitEthernet0/1 Yes GigabitEthernet0/2 No

Based on this output, which statement is correct?

Trap 1: DHCP relay information is trusted on both interfaces.

GigabitEthernet0/2 is not trusted.

Trap 2: DHCP relay information is not configured on any interface.

The output shows trust settings.

Trap 3: DHCP relay information is trusted on GigabitEthernet0/2, so option…

Untrusted interfaces drop option 82.

Study all DHCP (IPv4 and IPv6) common traps →

A
DHCP relay information is trusted on GigabitEthernet0/1, so option 82 packets are accepted on that interface.
Trusted interfaces accept option 82.
B
DHCP relay information is trusted on both interfaces.
Why wrong: GigabitEthernet0/2 is not trusted.
C
DHCP relay information is not configured on any interface.
Why wrong: The output shows trust settings.
D
DHCP relay information is trusted on GigabitEthernet0/2, so option 82 packets are dropped.
Why wrong: Untrusted interfaces drop option 82.

Full breakdown with real-world context →

Question 18mediummultiple choice

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A network engineer runs the following command on Router R1:

R1# show ip dhcp database

URL : flash:/dhcpdb Read/write : Read/Write Last updated : Mar 01 2020 00:00:00 Status : Last read succeeded. Next write scheduled in 0 seconds.

Based on this output, which statement is correct?

Trap 1: The DHCP database is stored in NVRAM and is read-only.

It is stored in flash and is read/write.

Trap 2: The DHCP database write failed and needs to be rescheduled.

The last read succeeded.

Trap 3: The DHCP database is empty because no bindings exist.

The output does not indicate emptiness.

Study all DHCP (IPv4 and IPv6) common traps →

A
The DHCP database is stored in NVRAM and is read-only.
Why wrong: It is stored in flash and is read/write.
B
The DHCP database is stored in flash and is functioning correctly.
The status shows success.
C
The DHCP database write failed and needs to be rescheduled.
Why wrong: The last read succeeded.
D
The DHCP database is empty because no bindings exist.
Why wrong: The output does not indicate emptiness.

Full breakdown with real-world context →

Question 19mediummultiple choice

Read the full DHCP explanation →

Examine the following DHCP configuration on router R1:

ip dhcp excluded-address 192.168.1.1 192.168.1.10

ip dhcp pool POOL1
 network 192.168.1.0 255.255.255.0

default-router 192.168.1.1 dns-server 8.8.8.8 lease 0 2 30 !

interface GigabitEthernet0/0
 ip address 192.168.1.1 255.255.255.0
 ip helper-address 192.168.2.2
 no shutdown

What is the effect of this configuration?

Trap 1: The ip helper-address command will be ignored because the router is…

The ip helper-address is not ignored; it still forwards broadcasts to the specified server, as the router does not automatically disable it when acting as a DHCP server.

Trap 2: The excluded-address range is misconfigured because it includes the…

Excluding the router's own IP is a best practice to avoid conflicts; the router will still function normally.

Trap 3: The DHCP pool will not assign addresses because the network…

The network 192.168.1.0 255.255.255.0 matches the interface subnet exactly, so it is valid.

Study all DHCP (IPv4 and IPv6) common traps →

A
Clients on the 192.168.1.0/24 subnet will receive IP addresses from the local DHCP pool, and the ip helper-address will forward DHCP requests to 192.168.2.2, causing duplicate offers.
The local DHCP server will respond to requests, but the helper address will also forward broadcasts to the remote server, leading to duplicate DHCP offers and potential address conflicts.
B
The ip helper-address command will be ignored because the router is the DHCP server for that subnet.
Why wrong: The ip helper-address is not ignored; it still forwards broadcasts to the specified server, as the router does not automatically disable it when acting as a DHCP server.
C
The excluded-address range is misconfigured because it includes the router's own interface IP, which will prevent the router from functioning.
Why wrong: Excluding the router's own IP is a best practice to avoid conflicts; the router will still function normally.
D
The DHCP pool will not assign addresses because the network statement does not match the interface subnet exactly.
Why wrong: The network 192.168.1.0 255.255.255.0 matches the interface subnet exactly, so it is valid.

Full breakdown with real-world context →

Question 20mediummultiple choice

Read the full DHCP explanation →

Consider the following DHCPv6 configuration on router R2:

ipv6 dhcp pool DHCP6_POOL dns-server 2001:db8::1 domain-name example.com !

interface GigabitEthernet0/0

ipv6 address 2001:db8:1::1/64 ipv6 dhcp server DHCP6_POOL ipv6 nd other-config-flag

no shutdown

What is the effect of this configuration?

Trap 1: Hosts will obtain both their IPv6 address and DNS information from…

The other-config-flag means DHCPv6 is only for other configuration, not for address assignment. For address assignment, the managed-config-flag would be needed.

Trap 2: The DHCPv6 pool is missing the address prefix, so it will not…

In stateless DHCPv6, the pool does not need an address prefix; it only provides other parameters like DNS and domain.

Trap 3: The ipv6 nd other-config-flag command is ignored because the DHCPv6…

The flag is not ignored; it works together with the DHCPv6 server to provide stateless configuration.

Study all DHCP (IPv4 and IPv6) common traps →

A
Hosts on this subnet will use SLAAC to obtain their IPv6 address and then use DHCPv6 to get DNS and domain information.
The other-config-flag indicates that hosts should use SLAAC for addressing and DHCPv6 for additional parameters, which is stateless DHCPv6.
B
Hosts will obtain both their IPv6 address and DNS information from the DHCPv6 pool.
Why wrong: The other-config-flag means DHCPv6 is only for other configuration, not for address assignment. For address assignment, the managed-config-flag would be needed.
C
The DHCPv6 pool is missing the address prefix, so it will not provide any configuration to clients.
Why wrong: In stateless DHCPv6, the pool does not need an address prefix; it only provides other parameters like DNS and domain.
D
The ipv6 nd other-config-flag command is ignored because the DHCPv6 server is configured on the interface.
Why wrong: The flag is not ignored; it works together with the DHCPv6 server to provide stateless configuration.

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Frequently asked questions

What does the 300-410 exam test about DHCP (IPv4 and IPv6)?: IPv6 questions usually test address types (link-local, global unicast, ULA), autoconfiguration (SLAAC), Neighbor Discovery Protocol and the differences from IPv4.
How should I use these practice questions?: Select your answer before revealing the explanation. Then read why each option is right or wrong — this active recall approach builds retention far faster than re-reading notes.
Can I practise just DHCP (IPv4 and IPv6) questions in a focused session?: Yes — the session launcher on this page draws every question from the DHCP (IPv4 and IPv6) domain. Use a 10-question session first to gauge your baseline, then move to 20 or 30 once the weak spots are clear.
Where can I practise other 300-410 topics?: Use the topic links above to move to related areas, or go back to the 300-410 question bank to see all topics.
Are these real exam questions or dumps?: These are original practice questions written to test the same concepts the 300-410 exam covers. They are not copied from any real exam or dump site.

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All 300-410 questions DHCP (IPv4 and IPv6) domain overview 300-410 exam guide

Exam traps to avoid

▸Link-local addresses are not routable beyond the local link.
▸SLAAC uses EUI-64 or random interface IDs — not a DHCP server.
▸NDP uses ICMPv6, not ARP.
▸An IPv6 prefix is /64 for most host subnets, not /24.

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