DNS Zone Types and DHCP Communication Protocols

Posted on Nov 13, 2025 in Contemporary Music Composition

Types of DNS Zones

Standard Primary Zones

This is a zone that hosts a read and write copy of the DNS zone in which records are produced and administered. Key characteristics include:

  • Only one primary server per zone is allowed.
  • This server loads and hosts the master copy of the zone.
  • It is the only server allowed to process dynamic updates and zone changes.
  • The primary server is generally located in a readily accessible location to allow administration of the zone file.

Standard Secondary Zones

One or more servers can be used to store a read-only copy of the primary DNS zone. Information is received from the primary through a zone transfer, which copies the zone file from the primary server to the secondary server.

These zone transfers can be:

  • Full: Transfers the complete zone contents each time.
  • Incremental: Transfers only changed information since the last transfer. Performing incremental transfers can reduce network traffic between servers.

When creating a secondary zone, you must provide the address of one or more master servers from which you wish to copy the zones.

Reverse Lookup Zones

While most DNS queries are forward queries (requesting an IP address based on providing a name), reverse lookup zones (also called in-addr.arpa domains) allow determination of a host’s name by providing its IP address.

Network applications frequently use reverse lookup queries for verification purposes, or to troubleshoot and monitor DNS functionality.

Stub Zones

DNS servers with Windows Server 2003 or Windows Server 2008 (and later) can also be configured as stub zones. These servers maintain a copy of the zone that only contains records necessary to identify authoritative DNS servers for its zone.

Think of it as a pointer used to provide DNS resolution efficiency. Using the stub zone’s list of name servers, a DNS server can resolve queries without querying the Internet or other internal root servers.

DHCP Lease Process Messages

The Dynamic Host Configuration Protocol (DHCP) uses several message types to manage IP address assignment and configuration.

DHCP Discover Message

A DHCP client sends a DHCP Discover broadcast on the network for finding a DHCP server. If there is no response from a DHCP server, the client assigns itself an Automatic Private IP Address (APIPA).

DHCP Offer Message

DHCP servers on a network that receive a DHCP Discover message respond with a DHCP Offer message, which offers the client an IP address lease.

DHCP Request Message

Clients accept the first offer received by broadcasting a DHCP Request message for the offered IP address.

DHCP Acknowledgment Message (ACK)

The server accepts the request by sending the client a DHCP Acknowledgment message.

DHCP NAK Message (Negative Acknowledgment)

If the IP address requested by the DHCP client cannot be used (e.g., another device may be using this IP address), the DHCP server responds with a DHCPNak packet. After this, the client must begin the DHCP lease process again.

DHCP Decline Message

If the DHCP client determines the offered TCP/IP configuration parameters are invalid, it sends a DHCP Decline packet to the server. After this, the client must begin the DHCP lease process again.

DHCP Release Message

A DHCP client sends a DHCP Release packet to the server to release the IP address and cancel any remaining lease.

DHCP Inform Message

DHCP Inform is a new DHCP message type, defined in RFC 2131. DHCP Inform is used by DHCP clients to obtain DHCP options (when they already have an IP address).