Apple's DNS Long-Lived Queries Protocol
S. Cheshire, M. Krochmal · 2020
Apple's Long-Lived Queries protocol (LLQ) is a protocol for extending the protocol to support change notification, thus allowing clients to learn about changes to data without polling the server. From 2005 onwards, LLQ was implemented in Apple products including Mac OS X, Bonjour for Windows, and AirPort wireless base stations. In 2019, the LLQ protocol was superseded by the IETF Standards Track RFC xxxx [[RFC Editor note: Please replace xxxx with RFC number]] DNS Push Notifications, which builds on experience gained with the LLQ protocol to create a superior replacement. The existing LLQ protocol deployed and used from 2005 to 2019 is documented here to give background regarding the operational experience that informed the development of Push Notifications, and to help facilitate a smooth transition from LLQ to Push Notifications.