Return Routability Check for DTLS 1.2 and 1.3
RFC 9853, “Return Routability Check for DTLS 1.2 and 1.3”, is a Proposed Standard document published in March 2026 by H. Tschofenig, A. Kraus, T. Fossati. It updates RFC 9146, RFC 9147. The canonical text is published by the RFC Editor.
Abstract
This document specifies a Return Routability Check (RRC) subprotocol for use in the context of the Connection ID (CID) construct for the Datagram Transport Layer Security (DTLS) protocol versions 1.2 and 1.3.
Implementations offering the CID functionality described in RFCs 9146 and 9147 are encouraged to also provide the RRC functionality described in this document. For this reason, this document updates RFCs 9146 and 9147.
What “Proposed Standard” means
An entry-level standards-track specification: stable, peer-reviewed and a solid basis for implementation, though it may still evolve before becoming an Internet Standard.
The canonical text of RFC 9853 is hosted at rfc-editor.org. Available in HTML,TXT,PDF,XML.
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