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"X-" Considered Harmful

Document type: Expired Internet-Draft (individual)
Document stream: No stream defined
Last updated: 2010-10-19
Intended RFC status: Unknown
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IESG State: Expired
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This Internet-Draft is no longer active. Unofficial copies of old Internet-Drafts can be found here:


Many application protocols use named parameters to represent data (for example, header fields in Internet mail messages and HTTP requests). Historically, protocol designers and implementers have often differentiated between "standard" and "experimental" parameters by prefixing experimental parameters with the string "X-". This document argues that, on balance, the "X-" convention has more costs than benefits.


Peter Saint-Andre <>

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