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Status:

PROPOSED STANDARD

Authors:

P. Wouters
J. Abley
S. Dickinson
R. Bellis

Stream:

IETF

Source:

dnsop (ops)

Cite this RFC:TXT  | XML  |  BibTeX

DOI:  https://doi.org/10.17487/RFC7828

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Abstract

DNS messages between clients and servers may be received over eitherUDP or TCP. UDP transport involves keeping less state on a busyserver, but can cause truncation and retries over TCP. Additionally,UDP can be exploited for reflection attacks. Using TCP would reduceretransmits and amplification. However, clients commonly use TCPonly for retries and servers typically use idle timeouts on the orderof seconds.

This document defines an EDNS0 option ("edns-tcp-keepalive") thatallows DNS servers to signal a variable idle timeout. Thissignalling encourages the use of long-lived TCP connections byallowing the state associated with TCP transport to be managedeffectively with minimal impact on the DNS transaction time.

For the definition ofStatus,seeRFC 2026.

For the definition ofStream, seeRFC 8729.