DHCP
The Dynamic Host Configuration Protocol automatically supplies hosts with IP addressing and other configuration. DHCPv4 and DHCPv6 are separate protocols with different message formats, transports, identifiers, and state models.
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97 definitions associated with DHCP.
Browse DHCP definitions
97 matching terms
Page 2 of 5DHCP client
A host or device that requests configuration from a DHCP server. The client can identify itself through a MAC address, client identifier, DUID, IAID, vendor class, or other fields depending on protocol version.
Read definitionDHCP failover
A protocol or product feature that allows two DHCP servers to coordinate lease ownership and continue service after a partner failure. DHCPv4 failover behavior and DHCPv6 failover use different standards and implementations.
Read definitionDHCP fingerprinting
Identification or classification of a client device based on the DHCP options it requests, sends, or orders. Fingerprints can support inventory, policy, NAC, and anomaly detection, but are not a strong identity mechanism.
Read definitionDHCP lease
A time-limited authorization for a client to use an address or prefix together with associated configuration. The client renews before expiration or stops using the resource when the lease is no longer valid.
Read definitionDHCP message type
A code identifying the purpose of a DHCP message, such as DISCOVER, OFFER, REQUEST, ACK, SOLICIT, ADVERTISE, or REPLY. DHCPv4 message type is carried in option 53, while DHCPv6 begins with a native message-type field.
Read definitionDHCP option
A typed field that carries configuration or protocol information in a DHCP exchange. Options can provide DNS servers, routes, boot parameters, identities, relay metadata, domain search lists, or vendor data.
Read definitionDHCP policy
A rule that matches client, relay, network, time, or option attributes and applies behavior such as a pool, option set, lease time, or deny action. Policy syntax and precedence are product-specific.
Read definitionDHCP relay agent
A router, switch, firewall, or server function that forwards DHCP messages between clients and servers on different links. It adds link-identifying information so the server can select the correct subnet or policy.
Read definitionDHCP reservation
A configuration that consistently assigns a chosen address to a known client. Matching can be based on client identifier, MAC address, DUID, or another product-supported key.
Read definitionDHCP scope
A defined IPv4 subnet and its allocatable address range, exclusions, reservations, lease duration, and options. Some products instead use terms such as network, range, pool, or subnet.
Read definitionDHCP server
A service that selects configuration for clients, maintains bindings, and responds to DHCP messages. It can also coordinate DNS updates, policy evaluation, failover, and lease reporting.
Read definitionDHCP starvation
An attack or fault in which many fake client identities consume the available address pool, preventing legitimate clients from obtaining leases. Rate limits, DHCP snooping, port security, and monitoring help mitigate it.
Read definitionDHCPv4
The DHCP protocol used to configure IPv4 hosts. It uses UDP ports 67 and 68 and commonly follows the Discover, Offer, Request, Acknowledge sequence.
Read definitionDHCPv4-over-DHCPv6
A mechanism that carries DHCPv4 messages through DHCPv6 infrastructure, useful in some IPv6-oriented access networks. It is identified by DHCPv6 DHCPV4-QUERY and DHCPV4-RESPONSE messages.
Read definitionDHCPv6
The DHCP protocol for IPv6. It uses UDP ports 546 and 547, DUID-based identities, identity associations, and messages such as SOLICIT, ADVERTISE, REQUEST, and REPLY.
Read definitionDNS search list
An ordered set of suffixes a host may append to a relative name during local resolution. DHCP options 119 and 24 can distribute search lists for IPv4 and IPv6 respectively.
Read definitionDynamic allocation
An allocation method that leases an address to a client for a limited time from a pool. The address can be returned and later assigned to another client after release or expiration.
Read definitionDynamic range
The portion of a subnet from which a server may select addresses for ordinary lease allocation. Reservations, fixed addresses, exclusions, and static infrastructure should be planned to avoid overlap.
Read definitionEnterprise number
A Private Enterprise Number assigned by IANA to an organization. DHCP vendor-specific identifiers, DUID-EN values, and many management protocols use enterprise numbers to distinguish namespaces.
Read definitionExclusion
An address or range inside a DHCP scope or subnet that the server must not lease dynamically. Exclusions are used to protect statically assigned infrastructure or address blocks managed elsewhere.
Read definitionExpired lease
A lease whose valid lifetime has ended. The server may return the address or prefix to an available state after any configured hold-down, cleanup, or conflict-check process.
Read definitionFailover association
A configured relationship between DHCP partners that defines peers, mode, shared address pools, timers, and state. Product implementations may call it a failover relationship, association, or peer relationship.
Read definitionFailover state
The current operational condition of a DHCP failover relationship, such as normal, communications interrupted, partner down, recover, or potential conflict. Exact state names depend on the protocol and product.
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