IETF RFC 6148 PDF

Abstract

Some relay agents extract lease information from the DHCP messages exchanged between the client and DHCP server. This lease information is used by relay agents for various purposes like antispoofing and prevention of flooding. RFC 4388 defines a mechanism for relay agents to retrieve the lease information from the DHCP server when this information is lost. The existing lease query mechanism is data-driven, which means that a relay agent can initiate the lease query only when it starts receiving data to and from the clients. In certain scenarios, this model is not scalable. This document first looks at issues in the existing mechanism and then proposes a new query type, query by Remote ID, to address these issues.