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Repeat And Request-Tag

Document Type Replaced Internet-Draft (individual)
Expired & archived
Authors Christian Amsüss , John Preuß Mattsson , Göran Selander
Last updated 2017-07-01
Replaces draft-amsuess-core-request-tag
Replaced by RFC 9175
RFC stream (None)
Intended RFC status (None)
Stream Stream state (No stream defined)
Consensus boilerplate Unknown
RFC Editor Note (None)
IESG IESG state Replaced by draft-ietf-core-echo-request-tag
Telechat date (None)
Responsible AD (None)
Send notices to (None)

This Internet-Draft is no longer active. A copy of the expired Internet-Draft is available in these formats:


This document defines two optional extensions to the Constrained Application Protocol (CoAP): the Repeat option and the Request-Tag option. Each of these options when integrity protected, such as with DTLS or OSCOAP, protects against certain attacks on CoAP message exchanges. The Repeat option enables a CoAP server to verify the freshness of a request by requiring the CoAP client to make another request and include a server-provided challenge. The Request-Tag option allows the CoAP server to match message fragments belonging to the same request message, fragmented using the CoAP Block-Wise Transfer mechanism. This document also specifies additional processing requirements on Block1 and Block2 options.


Christian Amsüss
John Preuß Mattsson
Göran Selander

(Note: The e-mail addresses provided for the authors of this Internet-Draft may no longer be valid.)