===== RFC6891 - Extension Mechanisms for DNS (EDNS(0)) =====
[[dido:public:ra:xapend:xapend.b_stds:tech:ietf:start| return to the IETF Standards ]]

<table>
<caption>Data sheet for RFC6891 Extension Mechanisms for DNS (EDNS(0))</caption>
| Title                      | Extension Mechanisms for DNS|
| Acronym                    | EDNS(0) |
| Version                    | 2013 |
| Document Number            | RFC6891 |
| Release Date               | April 2013  |
| Reference                  | [[https://tools.ietf.org/html/rfc6891]] |
</table>

  : **Note**: The following is an excerpt from the official IETF RFC. It is provided here as a convenience and is not authoritative. Refer to the original document as the authoritative reference.

==== Introduction ====
  : //The [[dido:public:ra:xapend:xapend.a_glossary:d:dns|Domain Name System's]] [[dido:public:ra:xapend:xapend.a_glossary:w:wireprotocol|wire protocol]] includes a number of fixed
   fields whose range has been or soon will be exhausted and does not
   allow requestors to advertise their capabilities to responders.  This
   document describes backward-compatible mechanisms for allowing the
   [[dido:public:ra:xapend:xapend.a_glossary:p:protocol|protocol]] to grow.//

  : //This document updates the Extension Mechanisms for [[dido:public:ra:xapend:xapend.a_glossary:d:dns]] (EDNS(0))
   specification (and obsoletes RFC 2671) based on feedback from
   deployment experience in several implementations.  It also obsoletes
   RFC 2673 ("Binary Labels in the Domain Name System") and adds
   considerations on the use of extended labels in the DNS.//


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