Address registration
A mechanism by which a host informs a DHCPv6 infrastructure component about an IPv6 address it configured through another method, such as SLAAC. This can help DDI systems maintain address visibility and DNS registration.
Category glossary
Search all termsDHCPv6
31 definitions associated with DHCPv6.
Delegated prefix
An IPv6 prefix assigned to a requesting router for use on downstream links. The router can subnet the delegated prefix without receiving individual address leases for every downstream host.
Delegating router
A DHCPv6 server function that selects and delegates IPv6 prefixes to requesting routers. It maintains prefix bindings and lifetimes in much the same way address leases are maintained.
DUID
A DHCP Unique Identifier that identifies a DHCPv6 client or server across interfaces and restarts. Defined types include link-layer plus time, enterprise-based, link-layer only, and UUID-based DUIDs.
IA
Identity Association, a DHCPv6 structure that groups one or more addresses or prefixes assigned to a client interface or purpose. Each IA is identified by an IAID and has associated timers and lifetimes.
IA Address option
The DHCPv6 option that carries an IPv6 address and its preferred and valid lifetimes within an identity association. It can also contain status or other address-specific suboptions.
IA_NA
Identity Association for Non-temporary Addresses. It is the standard DHCPv6 container used to request and assign ordinary stateful IPv6 addresses.
IA_PD
Identity Association for Prefix Delegation. It carries one or more delegated prefixes and related T1, T2, preferred, and valid lifetime information.
IA_TA
Identity Association for Temporary Addresses, an older DHCPv6 mechanism intended for temporary address assignment. RFC 9915 marks it obsolete.
IAID
Identity Association Identifier, a client-chosen value that distinguishes identity associations belonging to the same DUID. It is meaningful together with the client DUID and IA type.
IAPREFIX
The DHCPv6 option nested inside IA_PD that identifies a delegated IPv6 prefix and its preferred and valid lifetimes. It can also carry prefix-related status information.
IPv6 prefix delegation
The assignment of an IPv6 prefix to a requesting router through DHCPv6 so it can number downstream links. It is widely used for broadband, branch, home, mobile, and delegated tenant networks.
Link-address
A field in a Relay-forward message used to identify the client link to the DHCPv6 server. The server uses it to select appropriate address or prefix pools and options.
Non-temporary address
An ordinary stateful IPv6 address carried in an IA_NA, contrasted with the obsolete IA_TA temporary-address mechanism. The address still has preferred and valid lifetimes.
Option Request Option (ORO)
A DHCPv6 option containing the option codes a client wants the server to return. It is analogous to the DHCPv4 Parameter Request List.
ORO
Abbreviation for Option Request Option. A client lists desired configuration option codes in OPTION_ORO.
PD
Common abbreviation for Prefix Delegation. DHCPv6 PD assigns a prefix to a requesting router rather than only assigning a single interface address.
Peer-address
A field in a relay message identifying the client or previous relay from which the message was received. It helps preserve the relay chain and return path.
Preference
A relative selection value whose interpretation depends on the protocol. MX and SRV use numeric preference or priority, while DHCPv6 servers can send an OPTION_PREFERENCE value to influence client selection.
Preferred lifetime
The period during which an IPv6 address or prefix is preferred for new communication. After it expires but before valid lifetime ends, the resource is deprecated and should generally not be selected for new sessions.
Prefix delegation
A DHCPv6 function that assigns prefixes to routers for downstream use. It separates routed-prefix allocation from individual host-address assignment.
RECONFIGURE
A server-initiated DHCPv6 message asking a client to initiate Renew or Information-request processing. Clients must indicate and follow the applicable reconfigure acceptance and authentication rules.
Relay-forward
A DHCPv6 message created by a relay agent to encapsulate a client message or another relay message on its way to a server. Multiple relays can create a relay chain.
Relay-reply
A DHCPv6 message sent from a server or upstream relay back through the relay chain toward the client. It contains the encapsulated response in the Relay Message option.
Requesting router
A router that asks a delegating router for one or more IPv6 prefixes using DHCPv6 Prefix Delegation. It assigns subnets from the delegated space to downstream links.
SARR
A mnemonic for the common stateful DHCPv6 exchange: Solicit, Advertise, Request, Reply. Rapid Commit can reduce the exchange to Solicit and Reply when both client and server support it.
Server unicast
An older DHCPv6 feature that allowed clients to send some messages directly to a server address advertised in an option. RFC 9915 marks the Server Unicast option and UseMulticast behavior obsolete.
SOLICIT
The initial DHCPv6 client message used to locate servers and request addresses, prefixes, or other configuration. Servers normally answer with ADVERTISE unless Rapid Commit is used.
Stateful DHCPv6
DHCPv6 operation in which the server assigns addresses or prefixes and maintains bindings, typically through IA_NA or IA_PD. Router Advertisements still provide default-router information.
Stateless DHCPv6
DHCPv6 used only to provide configuration such as DNS or domain search information without assigning addresses. Clients normally learn addresses through SLAAC and send INFORMATION-REQUEST.
Valid lifetime
The period during which an IPv6 address or delegated prefix remains valid for existing and new use, subject to preferred-state rules. When it expires, the resource must not be used.