Deprecating Use of the "X-" Prefix in Application Protocols

Document Type Replaced Internet-Draft (individual)
Last updated 2011-09-14 (latest revision 2011-07-26)
Replaced by draft-ietf-appsawg-xdash
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This Internet-Draft is no longer active. A copy of the expired Internet-Draft can be found at


Historically, there has often been a perceived distinction between "standard" and "non-standard" parameters (such as media types and header fields), by prefixing the latter with the string "X-" or similar constructions (e.g., "x."). In practice, this convention causes more problems than it solves. Therefore, this document deprecates the "X-" convention for most application protocol parameters.


Peter Saint-Andre (
dcrocker (
mnot (

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