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Address-Resolution Protocols: Which One Is NOT Used? (DNS, ARP, DHCP, RARP)

Address-Resolution Protocols: Which One Is NOT Used? (DNS, ARP, DHCP, RARP)

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Nov 3, 2026

ARP vs RARP vs DHCP vs DNS (Networking Fundamentals)

In the question, “resolve one form of address to another” means mapping between different address types used at different layers (e.g., IP ↔ MAC, or name ↔ IP).

  • ARP resolves an IPv4 address to a MAC (link-layer) address.
  • RARP resolves a MAC address to an IPv4 address (a reverse mapping).
  • DNS resolves a domain name (hostname) to an IP address.
  • DHCP, however, is primarily used to automatically assign IP addresses and configuration parameters, not to perform a direct address-resolution mapping between two address formats.

Therefore, the protocol that is NOT used to resolve one form of address to another (as implied by the mapping/resolution pairs for ARP and RARP, and name-to-IP for DNS) is: (iii) DHCP.

Footnotes

  1. Address Resolution Protocol - Wikipedia - ARP discovers the MAC address associated with an IPv4 address (IP → MAC). ↩

  2. Reverse Address Resolution Protocol - Wikipedia - RARP maps a link-layer (MAC) address to its IPv4 address (MAC → IP). ↩

  3. What Is DNS Resolution? How It Works & Best Practices | New Relic - DNS resolution translates domain names into IP addresses used for routing. ↩

  4. Dynamic Host Configuration Protocol - Wikipedia - DHCP automatically assigns IP addresses and other communication parameters via a client–server lease model. ↩

Core ideas and key definitions

  • Address Resolution
  • MAC Address
  • IP Address
  • DNS Resolution
  • DHCP Lease

Resolution-style protocols in this list perform a direct mapping:

  • ARP: IP → MAC
  • RARP: MAC → IP
  • DNS: Name → IP

DHCP is different: it’s a configuration/assignment protocol for giving devices an IP address and other settings, using a lease model.

Footnotes

  1. Address Resolution Protocol - Wikipedia - ARP discovers the MAC address associated with an IPv4 address (IP → MAC). ↩

  2. Reverse Address Resolution Protocol - Wikipedia - RARP maps a link-layer (MAC) address to its IPv4 address (MAC → IP). ↩

  3. What Is DNS Resolution? How It Works & Best Practices | New Relic - DNS resolution translates domain names into IP addresses used for routing. ↩

  4. Dynamic Host Configuration Protocol - Wikipedia - DHCP automatically assigns IP addresses and other communication parameters via a client–server lease model. ↩

How to identify the NOT-used protocol in an address-resolution question

  1. 1
    Step 1

    Look for protocols that perform a direct mapping from one address type to another (e.g., IP↔MAC, name↔IP).

  2. 2
    Step 2

    Confirm that ARP maps an IPv4 address to a MAC address within the local network.

    Footnotes

    1. Address Resolution Protocol - Wikipedia - ARP discovers the MAC address associated with an IPv4 address (IP → MAC). ↩

  3. 3
    Step 3

    Confirm that RARP performs the reverse mapping: MAC address to IPv4 address.

    Footnotes

    1. Reverse Address Resolution Protocol - Wikipedia - RARP maps a link-layer (MAC) address to its IPv4 address (MAC → IP). ↩

  4. 4
    Step 4

    Confirm that DNS resolution converts domain names into IP addresses.

    Footnotes

    1. What Is DNS Resolution? How It Works & Best Practices | New Relic - DNS resolution translates domain names into IP addresses used for routing. ↩

  5. 5
    Step 5

    Confirm that DHCP assigns IP addresses and configuration parameters via client–server leasing, rather than being a direct address-mapping/resolution mechanism.

    Footnotes

    1. Dynamic Host Configuration Protocol - Wikipedia - DHCP automatically assigns IP addresses and other communication parameters via a client–server lease model. ↩

  6. 6
    Step 6

    That protocol is DHCP.

Exam shortcut

If you see ARP/RARP, think IP ↔ MAC (direct address mapping). If you see DNS, think name ↔ IP. DHCP is assignment/config, not mapping.

Common confusion

DHCP can provide a device’s IP (and sometimes DNS server addresses), but the question asks which protocol is NOT used to resolve one form of address to another. That direct “resolution mapping” role is carried out by ARP/RARP/DNS, not DHCP. 4

Footnotes

  1. Dynamic Host Configuration Protocol - Wikipedia - DHCP automatically assigns IP addresses and other communication parameters via a client–server lease model. ↩

  2. Address Resolution Protocol - Wikipedia - ARP discovers the MAC address associated with an IPv4 address (IP → MAC). ↩

  3. Reverse Address Resolution Protocol - Wikipedia - RARP maps a link-layer (MAC) address to its IPv4 address (MAC → IP). ↩

  4. What Is DNS Resolution? How It Works & Best Practices | New Relic - DNS resolution translates domain names into IP addresses used for routing. ↩

Where each protocol fits in address mapping vs configuration

ARP / RARP

Link layer (Ethernet delivery)

ARP maps IP → MAC; RARP maps MAC → IP. 2"

Footnotes

  1. Address Resolution Protocol - Wikipedia - ARP discovers the MAC address associated with an IPv4 address (IP → MAC). ↩

  2. Reverse Address Resolution Protocol - Wikipedia - RARP maps a link-layer (MAC) address to its IPv4 address (MAC → IP). ↩

DNS

Application/internet naming

DNS maps domain name → IP address. "

Footnotes

  1. What Is DNS Resolution? How It Works & Best Practices | New Relic - DNS resolution translates domain names into IP addresses used for routing. ↩

DHCP

Network configuration/bootstrap

DHCP assigns IP address and other parameters using a lease. "

Footnotes

  1. Dynamic Host Configuration Protocol - Wikipedia - DHCP automatically assigns IP addresses and other communication parameters via a client–server lease model. ↩

Protocol role in this question (resolution mapping vs configuration)

Direct mapping between address formats vs IP/config assignment

Quick FAQ

Knowledge Check

Question 1 of 4
Q1Single choice

Which one of the following protocols is NOT used to resolve one form of address to another one? (i) DNS (ii) ARP (iii) DHCP (iv) RARP

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