CompTIA Network+ N10-009 DHCP DNS IPv6 Addressing And Time Services Practice Test

 

Objective 3.4 • 20 original questions

This CompTIA Network+ N10-009 practice test focuses on IPv4 and IPv6 network services. All questions are original ExamSnap scenarios aligned to the current N10-009 blueprint; they are not copied from CompTIA exam content. Use the complete N10-009 collection for broader practice across all five domains. For broader exam preparation, review the CompTIA Network+ N10-009 Exam Dumps page.

Instructions: Select the best answer for each question. Review the explanation after answering; each distractor includes a reason it is not the best choice for that scenario.

Question 1

At Litware Manufacturing, a systems administrator is reviewing a network change. The requirement is to give a device a predictable DHCP address without manually configuring it. Which option is the best fit? The decision applies to a branch-office rollout.

1. DHCP reservation
2. PTP
3. DoH
4. Authoritative DNS
5. A record

Correct answer: A

Why: Maps a client identifier/MAC to a consistent leased IP address. This directly satisfies the requirement: give a device a predictable DHCP address without manually configuring it.

Option review:

A: Maps a client identifier/MAC to a consistent leased IP address. This directly satisfies the requirement: give a device a predictable DHCP address without manually configuring it.

B: Provides much more precise time synchronization for environments such as industrial or financial systems. However, it does not most directly satisfy the requirement in this scenario: give a device a predictable DHCP address without manually configuring it.

C: Carries DNS queries inside HTTPS. However, it does not most directly satisfy the requirement in this scenario: give a device a predictable DHCP address without manually configuring it.

D: Answers from authoritative zone data rather than recursion/cache. However, it does not most directly satisfy the requirement in this scenario: give a device a predictable DHCP address without manually configuring it.

E: Maps a DNS name to an IPv4 address. However, it does not most directly satisfy the requirement in this scenario: give a device a predictable DHCP address without manually configuring it.

Learning point: Use DHCP reservation when the key requirement is to give a device a predictable DHCP address without manually configuring it.

Question 2

A ticket at Woodgrove Bank says the team must specify which IPv4 addresses a DHCP server can lease on a subnet. Which technology or concept most directly addresses this requirement? The decision applies to a campus refresh.

1. NTP
2. NS record
3. DHCP scope
4. Hosts file
5. DNSSEC

Correct answer: C

Why: Defines the address pool and options available to clients on a subnet. This directly satisfies the requirement: specify which IPv4 addresses a DHCP server can lease on a subnet.

Option review:

A: Synchronizes system clocks over IP networks, commonly with millisecond-level precision. However, it does not most directly satisfy the requirement in this scenario: specify which IPv4 addresses a DHCP server can lease on a subnet.

B: Identifies authoritative name servers for a DNS zone. However, it does not most directly satisfy the requirement in this scenario: specify which IPv4 addresses a DHCP server can lease on a subnet.

C: Defines the address pool and options available to clients on a subnet. This directly satisfies the requirement: specify which IPv4 addresses a DHCP server can lease on a subnet.

D: Provides local static name-to-address mappings before or alongside DNS resolution. However, it does not most directly satisfy the requirement in this scenario: specify which IPv4 addresses a DHCP server can lease on a subnet.

E: Adds cryptographic validation to DNS data to help detect tampering/forgery. However, it does not most directly satisfy the requirement in this scenario: specify which IPv4 addresses a DHCP server can lease on a subnet.

Learning point: Use DHCP scope when the key requirement is to specify which IPv4 addresses a DHCP server can lease on a subnet.

Question 3

During a design meeting at Blue Yonder Airlines, the junior network administrator needs to adjust how frequently clients renew dynamically assigned addresses. What should be selected? The decision applies to a data-center segment.

1. PTP
2. DoH
3. DHCP lease time
4. NS record
5. TXT record

Correct answer: C

Why: Controls how long a client may use an assigned address before renewal. This directly satisfies the requirement: adjust how frequently clients renew dynamically assigned addresses.

Option review:

A: Provides much more precise time synchronization for environments such as industrial or financial systems. However, it does not most directly satisfy the requirement in this scenario: adjust how frequently clients renew dynamically assigned addresses.

B: Carries DNS queries inside HTTPS. However, it does not most directly satisfy the requirement in this scenario: adjust how frequently clients renew dynamically assigned addresses.

C: Controls how long a client may use an assigned address before renewal. This directly satisfies the requirement: adjust how frequently clients renew dynamically assigned addresses.

D: Identifies authoritative name servers for a DNS zone. However, it does not most directly satisfy the requirement in this scenario: adjust how frequently clients renew dynamically assigned addresses.

E: Stores arbitrary text often used for domain verification and email-security policies. However, it does not most directly satisfy the requirement in this scenario: adjust how frequently clients renew dynamically assigned addresses.

Learning point: Use DHCP lease time when the key requirement is to adjust how frequently clients renew dynamically assigned addresses.

Question 4

Contoso Health is updating its network standard. Which option best meets the need to automatically deliver gateway or DNS settings along with an IP address? The decision applies to a remote-site migration.

1. DHCP reservation
2. DoH
3. DHCP option
4. Hosts file
5. A record

Correct answer: C

Why: Provides extra settings such as default gateway or DNS servers to clients. This directly satisfies the requirement: automatically deliver gateway or DNS settings along with an IP address.

Option review:

A: Maps a client identifier/MAC to a consistent leased IP address. However, it does not most directly satisfy the requirement in this scenario: automatically deliver gateway or DNS settings along with an IP address.

B: Carries DNS queries inside HTTPS. However, it does not most directly satisfy the requirement in this scenario: automatically deliver gateway or DNS settings along with an IP address.

C: Provides extra settings such as default gateway or DNS servers to clients. This directly satisfies the requirement: automatically deliver gateway or DNS settings along with an IP address.

D: Provides local static name-to-address mappings before or alongside DNS resolution. However, it does not most directly satisfy the requirement in this scenario: automatically deliver gateway or DNS settings along with an IP address.

E: Maps a DNS name to an IPv4 address. However, it does not most directly satisfy the requirement in this scenario: automatically deliver gateway or DNS settings along with an IP address.

Learning point: Use DHCP option when the key requirement is to automatically deliver gateway or DNS settings along with an IP address.

Question 5

A field technician at Litware Manufacturing is validating a proposed solution. The design must serve clients on a different subnet without placing a DHCP server on every VLAN. Which answer is most appropriate? The decision applies to a operations lab.

1. DHCP relay/IP helper
2. DHCP exclusion
3. CNAME record
4. NTP
5. TXT record

Correct answer: A

Why: Forwards DHCP broadcasts between subnets to a remote DHCP server. This directly satisfies the requirement: serve clients on a different subnet without placing a DHCP server on every VLAN.

Option review:

A: Forwards DHCP broadcasts between subnets to a remote DHCP server. This directly satisfies the requirement: serve clients on a different subnet without placing a DHCP server on every VLAN.

B: Removes selected addresses from a scope so they are not dynamically leased. However, it does not most directly satisfy the requirement in this scenario: serve clients on a different subnet without placing a DHCP server on every VLAN.

C: Creates an alias from one DNS name to another canonical name. However, it does not most directly satisfy the requirement in this scenario: serve clients on a different subnet without placing a DHCP server on every VLAN.

D: Synchronizes system clocks over IP networks, commonly with millisecond-level precision. However, it does not most directly satisfy the requirement in this scenario: serve clients on a different subnet without placing a DHCP server on every VLAN.

E: Stores arbitrary text often used for domain verification and email-security policies. However, it does not most directly satisfy the requirement in this scenario: serve clients on a different subnet without placing a DHCP server on every VLAN.

Learning point: Use DHCP relay/IP helper when the key requirement is to serve clients on a different subnet without placing a DHCP server on every VLAN.

Question 6

For a new deployment at Woodgrove Bank, the networking team wants to reserve part of a DHCP range for statically addressed infrastructure. Which choice most directly satisfies the goal? The decision applies to a production maintenance window.

1. DHCP exclusion
2. DNSSEC
3. NS record
4. MX record
5. DHCP option

Correct answer: A

Why: Removes selected addresses from a scope so they are not dynamically leased. This directly satisfies the requirement: reserve part of a DHCP range for statically addressed infrastructure.

Option review:

A: Removes selected addresses from a scope so they are not dynamically leased. This directly satisfies the requirement: reserve part of a DHCP range for statically addressed infrastructure.

B: Adds cryptographic validation to DNS data to help detect tampering/forgery. However, it does not most directly satisfy the requirement in this scenario: reserve part of a DHCP range for statically addressed infrastructure.

C: Identifies authoritative name servers for a DNS zone. However, it does not most directly satisfy the requirement in this scenario: reserve part of a DHCP range for statically addressed infrastructure.

D: Identifies mail servers for a DNS domain. However, it does not most directly satisfy the requirement in this scenario: reserve part of a DHCP range for statically addressed infrastructure.

E: Provides extra settings such as default gateway or DNS servers to clients. However, it does not most directly satisfy the requirement in this scenario: reserve part of a DHCP range for statically addressed infrastructure.

Learning point: Use DHCP exclusion when the key requirement is to reserve part of a DHCP range for statically addressed infrastructure.

Question 7

At Blue Yonder Airlines, a systems administrator is reviewing a network change. The requirement is to allow IPv6 hosts to build addresses automatically from router advertisements. Which option is the best fit? The decision applies to a new floor deployment.

1. SLAAC
2. NS record
3. DHCP exclusion
4. NTS
5. DHCP option

Correct answer: A

Why: Lets IPv6 hosts self-configure addresses using router advertisements without stateful DHCPv6 addressing. This directly satisfies the requirement: allow IPv6 hosts to build addresses automatically from router advertisements.

Option review:

A: Lets IPv6 hosts self-configure addresses using router advertisements without stateful DHCPv6 addressing. This directly satisfies the requirement: allow IPv6 hosts to build addresses automatically from router advertisements.

B: Identifies authoritative name servers for a DNS zone. However, it does not most directly satisfy the requirement in this scenario: allow IPv6 hosts to build addresses automatically from router advertisements.

C: Removes selected addresses from a scope so they are not dynamically leased. However, it does not most directly satisfy the requirement in this scenario: allow IPv6 hosts to build addresses automatically from router advertisements.

D: Adds cryptographic security to NTP to authenticate time synchronization. However, it does not most directly satisfy the requirement in this scenario: allow IPv6 hosts to build addresses automatically from router advertisements.

E: Provides extra settings such as default gateway or DNS servers to clients. However, it does not most directly satisfy the requirement in this scenario: allow IPv6 hosts to build addresses automatically from router advertisements.

Learning point: Use SLAAC when the key requirement is to allow IPv6 hosts to build addresses automatically from router advertisements.

Question 8

A ticket at Contoso Health says the team must publish the IPv4 address for a hostname. Which technology or concept most directly addresses this requirement? The decision applies to a service-recovery review.

1. CNAME record
2. SLAAC
3. NTP
4. PTR record
5. A record

Correct answer: E

Why: Maps a DNS name to an IPv4 address. This directly satisfies the requirement: publish the IPv4 address for a hostname.

Option review:

A: Creates an alias from one DNS name to another canonical name. However, it does not most directly satisfy the requirement in this scenario: publish the IPv4 address for a hostname.

B: Lets IPv6 hosts self-configure addresses using router advertisements without stateful DHCPv6 addressing. However, it does not most directly satisfy the requirement in this scenario: publish the IPv4 address for a hostname.

C: Synchronizes system clocks over IP networks, commonly with millisecond-level precision. However, it does not most directly satisfy the requirement in this scenario: publish the IPv4 address for a hostname.

D: Maps an IP address back to a hostname in a reverse-lookup zone. However, it does not most directly satisfy the requirement in this scenario: publish the IPv4 address for a hostname.

E: Maps a DNS name to an IPv4 address. This directly satisfies the requirement: publish the IPv4 address for a hostname.

Learning point: Use A record when the key requirement is to publish the IPv4 address for a hostname.

Question 9

During a design meeting at Litware Manufacturing, the junior network administrator needs to publish the IPv6 address for a hostname. What should be selected? The decision applies to a branch-office rollout.

1. AAAA record
2. SLAAC
3. DoT
4. A record
5. NTS

Correct answer: A

Why: Maps a DNS name to an IPv6 address. This directly satisfies the requirement: publish the IPv6 address for a hostname.

Option review:

A: Maps a DNS name to an IPv6 address. This directly satisfies the requirement: publish the IPv6 address for a hostname.

B: Lets IPv6 hosts self-configure addresses using router advertisements without stateful DHCPv6 addressing. However, it does not most directly satisfy the requirement in this scenario: publish the IPv6 address for a hostname.

C: Carries DNS queries inside a dedicated TLS connection. However, it does not most directly satisfy the requirement in this scenario: publish the IPv6 address for a hostname.

D: Maps a DNS name to an IPv4 address. However, it does not most directly satisfy the requirement in this scenario: publish the IPv6 address for a hostname.

E: Adds cryptographic security to NTP to authenticate time synchronization. However, it does not most directly satisfy the requirement in this scenario: publish the IPv6 address for a hostname.

Learning point: Use AAAA record when the key requirement is to publish the IPv6 address for a hostname.

Question 10

Woodgrove Bank is updating its network standard. Which option best meets the need to make one hostname an alias of another hostname? The decision applies to a campus refresh.

1. DHCP reservation
2. DHCP exclusion
3. TXT record
4. DHCP lease time
5. CNAME record

Correct answer: E

Why: Creates an alias from one DNS name to another canonical name. This directly satisfies the requirement: make one hostname an alias of another hostname.

Option review:

A: Maps a client identifier/MAC to a consistent leased IP address. However, it does not most directly satisfy the requirement in this scenario: make one hostname an alias of another hostname.

B: Removes selected addresses from a scope so they are not dynamically leased. However, it does not most directly satisfy the requirement in this scenario: make one hostname an alias of another hostname.

C: Stores arbitrary text often used for domain verification and email-security policies. However, it does not most directly satisfy the requirement in this scenario: make one hostname an alias of another hostname.

D: Controls how long a client may use an assigned address before renewal. However, it does not most directly satisfy the requirement in this scenario: make one hostname an alias of another hostname.

E: Creates an alias from one DNS name to another canonical name. This directly satisfies the requirement: make one hostname an alias of another hostname.

Learning point: Use CNAME record when the key requirement is to make one hostname an alias of another hostname.

Question 11

A field technician at Blue Yonder Airlines is validating a proposed solution. The design must specify which server receives email for a domain. Which answer is most appropriate? The decision applies to a data-center segment.

1. NS record
2. MX record
3. DHCP reservation
4. PTP
5. DHCP lease time

Correct answer: B

Why: Identifies mail servers for a DNS domain. This directly satisfies the requirement: specify which server receives email for a domain.

Option review:

A: Identifies authoritative name servers for a DNS zone. However, it does not most directly satisfy the requirement in this scenario: specify which server receives email for a domain.

B: Identifies mail servers for a DNS domain. This directly satisfies the requirement: specify which server receives email for a domain.

C: Maps a client identifier/MAC to a consistent leased IP address. However, it does not most directly satisfy the requirement in this scenario: specify which server receives email for a domain.

D: Provides much more precise time synchronization for environments such as industrial or financial systems. However, it does not most directly satisfy the requirement in this scenario: specify which server receives email for a domain.

E: Controls how long a client may use an assigned address before renewal. However, it does not most directly satisfy the requirement in this scenario: specify which server receives email for a domain.

Learning point: Use MX record when the key requirement is to specify which server receives email for a domain.

Question 12

For a new deployment at Contoso Health, the networking team wants to publish verification or policy text in DNS. Which choice most directly satisfies the goal? The decision applies to a remote-site migration.

1. TXT record
2. DoH
3. A record
4. DHCP relay/IP helper
5. NTP

Correct answer: A

Why: Stores arbitrary text often used for domain verification and email-security policies. This directly satisfies the requirement: publish verification or policy text in DNS.

Option review:

A: Stores arbitrary text often used for domain verification and email-security policies. This directly satisfies the requirement: publish verification or policy text in DNS.

B: Carries DNS queries inside HTTPS. However, it does not most directly satisfy the requirement in this scenario: publish verification or policy text in DNS.

C: Maps a DNS name to an IPv4 address. However, it does not most directly satisfy the requirement in this scenario: publish verification or policy text in DNS.

D: Forwards DHCP broadcasts between subnets to a remote DHCP server. However, it does not most directly satisfy the requirement in this scenario: publish verification or policy text in DNS.

E: Synchronizes system clocks over IP networks, commonly with millisecond-level precision. However, it does not most directly satisfy the requirement in this scenario: publish verification or policy text in DNS.

Learning point: Use TXT record when the key requirement is to publish verification or policy text in DNS.

Question 13

At Litware Manufacturing, a systems administrator is reviewing a network change. The requirement is to delegate or identify the DNS servers authoritative for a zone. Which option is the best fit? The decision applies to a operations lab.

1. DHCP exclusion
2. DoH
3. Recursive DNS
4. DNSSEC
5. NS record

Correct answer: E

Why: Identifies authoritative name servers for a DNS zone. This directly satisfies the requirement: delegate or identify the DNS servers authoritative for a zone.

Option review:

A: Removes selected addresses from a scope so they are not dynamically leased. However, it does not most directly satisfy the requirement in this scenario: delegate or identify the DNS servers authoritative for a zone.

B: Carries DNS queries inside HTTPS. However, it does not most directly satisfy the requirement in this scenario: delegate or identify the DNS servers authoritative for a zone.

C: Queries other DNS servers on behalf of a client until it obtains an answer. However, it does not most directly satisfy the requirement in this scenario: delegate or identify the DNS servers authoritative for a zone.

D: Adds cryptographic validation to DNS data to help detect tampering/forgery. However, it does not most directly satisfy the requirement in this scenario: delegate or identify the DNS servers authoritative for a zone.

E: Identifies authoritative name servers for a DNS zone. This directly satisfies the requirement: delegate or identify the DNS servers authoritative for a zone.

Learning point: Use NS record when the key requirement is to delegate or identify the DNS servers authoritative for a zone.

Question 14

A ticket at Woodgrove Bank says the team must perform reverse DNS resolution from address to name. Which technology or concept most directly addresses this requirement? The decision applies to a production maintenance window.

1. PTR record
2. NS record
3. DNSSEC
4. DHCP lease time
5. NTP

Correct answer: A

Why: Maps an IP address back to a hostname in a reverse-lookup zone. This directly satisfies the requirement: perform reverse DNS resolution from address to name.

Option review:

A: Maps an IP address back to a hostname in a reverse-lookup zone. This directly satisfies the requirement: perform reverse DNS resolution from address to name.

B: Identifies authoritative name servers for a DNS zone. However, it does not most directly satisfy the requirement in this scenario: perform reverse DNS resolution from address to name.

C: Adds cryptographic validation to DNS data to help detect tampering/forgery. However, it does not most directly satisfy the requirement in this scenario: perform reverse DNS resolution from address to name.

D: Controls how long a client may use an assigned address before renewal. However, it does not most directly satisfy the requirement in this scenario: perform reverse DNS resolution from address to name.

E: Synchronizes system clocks over IP networks, commonly with millisecond-level precision. However, it does not most directly satisfy the requirement in this scenario: perform reverse DNS resolution from address to name.

Learning point: Use PTR record when the key requirement is to perform reverse DNS resolution from address to name.

Question 15

During a design meeting at Blue Yonder Airlines, the junior network administrator needs to validate that DNS responses are authentic and have not been modified. What should be selected? The decision applies to a new floor deployment.

1. Recursive DNS
2. SLAAC
3. MX record
4. DNSSEC
5. NTS

Correct answer: D

Why: Adds cryptographic validation to DNS data to help detect tampering/forgery. This directly satisfies the requirement: validate that DNS responses are authentic and have not been modified.

Option review:

A: Queries other DNS servers on behalf of a client until it obtains an answer. However, it does not most directly satisfy the requirement in this scenario: validate that DNS responses are authentic and have not been modified.

B: Lets IPv6 hosts self-configure addresses using router advertisements without stateful DHCPv6 addressing. However, it does not most directly satisfy the requirement in this scenario: validate that DNS responses are authentic and have not been modified.

C: Identifies mail servers for a DNS domain. However, it does not most directly satisfy the requirement in this scenario: validate that DNS responses are authentic and have not been modified.

D: Adds cryptographic validation to DNS data to help detect tampering/forgery. This directly satisfies the requirement: validate that DNS responses are authentic and have not been modified.

E: Adds cryptographic security to NTP to authenticate time synchronization. However, it does not most directly satisfy the requirement in this scenario: validate that DNS responses are authentic and have not been modified.

Learning point: Use DNSSEC when the key requirement is to validate that DNS responses are authentic and have not been modified.

Question 16

Contoso Health is updating its network standard. Which option best meets the need to encrypt DNS queries using HTTPS transport? The decision applies to a service-recovery review.

1. DoH
2. Hosts file
3. DoT
4. DHCP exclusion
5. MX record

Correct answer: A

Why: Carries DNS queries inside HTTPS. This directly satisfies the requirement: encrypt DNS queries using HTTPS transport.

Option review:

A: Carries DNS queries inside HTTPS. This directly satisfies the requirement: encrypt DNS queries using HTTPS transport.

B: Provides local static name-to-address mappings before or alongside DNS resolution. However, it does not most directly satisfy the requirement in this scenario: encrypt DNS queries using HTTPS transport.

C: Carries DNS queries inside a dedicated TLS connection. However, it does not most directly satisfy the requirement in this scenario: encrypt DNS queries using HTTPS transport.

D: Removes selected addresses from a scope so they are not dynamically leased. However, it does not most directly satisfy the requirement in this scenario: encrypt DNS queries using HTTPS transport.

E: Identifies mail servers for a DNS domain. However, it does not most directly satisfy the requirement in this scenario: encrypt DNS queries using HTTPS transport.

Learning point: Use DoH when the key requirement is to encrypt DNS queries using HTTPS transport.

Question 17

A field technician at Litware Manufacturing is validating a proposed solution. The design must encrypt DNS queries using DNS-over-TLS. Which answer is most appropriate? The decision applies to a branch-office rollout.

1. DHCP relay/IP helper
2. DoT
3. DHCP exclusion
4. MX record
5. Authoritative DNS

Correct answer: B

Why: Carries DNS queries inside a dedicated TLS connection. This directly satisfies the requirement: encrypt DNS queries using DNS-over-TLS.

Option review:

A: Forwards DHCP broadcasts between subnets to a remote DHCP server. However, it does not most directly satisfy the requirement in this scenario: encrypt DNS queries using DNS-over-TLS.

B: Carries DNS queries inside a dedicated TLS connection. This directly satisfies the requirement: encrypt DNS queries using DNS-over-TLS.

C: Removes selected addresses from a scope so they are not dynamically leased. However, it does not most directly satisfy the requirement in this scenario: encrypt DNS queries using DNS-over-TLS.

D: Identifies mail servers for a DNS domain. However, it does not most directly satisfy the requirement in this scenario: encrypt DNS queries using DNS-over-TLS.

E: Answers from authoritative zone data rather than recursion/cache. However, it does not most directly satisfy the requirement in this scenario: encrypt DNS queries using DNS-over-TLS.

Learning point: Use DoT when the key requirement is to encrypt DNS queries using DNS-over-TLS.

Question 18

For a new deployment at Woodgrove Bank, the networking team wants to serve the official records for a DNS zone. Which choice most directly satisfies the goal? The decision applies to a campus refresh.

1. NTP
2. DHCP reservation
3. CNAME record
4. Authoritative DNS
5. DHCP lease time

Correct answer: D

Why: Answers from authoritative zone data rather than recursion/cache. This directly satisfies the requirement: serve the official records for a DNS zone.

Option review:

A: Synchronizes system clocks over IP networks, commonly with millisecond-level precision. However, it does not most directly satisfy the requirement in this scenario: serve the official records for a DNS zone.

B: Maps a client identifier/MAC to a consistent leased IP address. However, it does not most directly satisfy the requirement in this scenario: serve the official records for a DNS zone.

C: Creates an alias from one DNS name to another canonical name. However, it does not most directly satisfy the requirement in this scenario: serve the official records for a DNS zone.

D: Answers from authoritative zone data rather than recursion/cache. This directly satisfies the requirement: serve the official records for a DNS zone.

E: Controls how long a client may use an assigned address before renewal. However, it does not most directly satisfy the requirement in this scenario: serve the official records for a DNS zone.

Learning point: Use Authoritative DNS when the key requirement is to serve the official records for a DNS zone.

Question 19

At Blue Yonder Airlines, a systems administrator is reviewing a network change. The requirement is to resolve external names for clients by performing recursive lookups. Which option is the best fit? The decision applies to a data-center segment.

1. TXT record
2. A record
3. DHCP relay/IP helper
4. PTP
5. Recursive DNS

Correct answer: E

Why: Queries other DNS servers on behalf of a client until it obtains an answer. This directly satisfies the requirement: resolve external names for clients by performing recursive lookups.

Option review:

A: Stores arbitrary text often used for domain verification and email-security policies. However, it does not most directly satisfy the requirement in this scenario: resolve external names for clients by performing recursive lookups.

B: Maps a DNS name to an IPv4 address. However, it does not most directly satisfy the requirement in this scenario: resolve external names for clients by performing recursive lookups.

C: Forwards DHCP broadcasts between subnets to a remote DHCP server. However, it does not most directly satisfy the requirement in this scenario: resolve external names for clients by performing recursive lookups.

D: Provides much more precise time synchronization for environments such as industrial or financial systems. However, it does not most directly satisfy the requirement in this scenario: resolve external names for clients by performing recursive lookups.

E: Queries other DNS servers on behalf of a client until it obtains an answer. This directly satisfies the requirement: resolve external names for clients by performing recursive lookups.

Learning point: Use Recursive DNS when the key requirement is to resolve external names for clients by performing recursive lookups.

Question 20

A ticket at Contoso Health says the team must override or test name resolution on a single host without changing DNS. Which technology or concept most directly addresses this requirement? The decision applies to a remote-site migration.

1. MX record
2. DHCP relay/IP helper
3. Authoritative DNS
4. Hosts file
5. NTS

Correct answer: D

Why: Provides local static name-to-address mappings before or alongside DNS resolution. This directly satisfies the requirement: override or test name resolution on a single host without changing DNS.

Option review:

A: Identifies mail servers for a DNS domain. However, it does not most directly satisfy the requirement in this scenario: override or test name resolution on a single host without changing DNS.

B: Forwards DHCP broadcasts between subnets to a remote DHCP server. However, it does not most directly satisfy the requirement in this scenario: override or test name resolution on a single host without changing DNS.

C: Answers from authoritative zone data rather than recursion/cache. However, it does not most directly satisfy the requirement in this scenario: override or test name resolution on a single host without changing DNS.

D: Provides local static name-to-address mappings before or alongside DNS resolution. This directly satisfies the requirement: override or test name resolution on a single host without changing DNS.

E: Adds cryptographic security to NTP to authenticate time synchronization. However, it does not most directly satisfy the requirement in this scenario: override or test name resolution on a single host without changing DNS.

Learning point: Use Hosts file when the key requirement is to override or test name resolution on a single host without changing DNS.