Return-Path: X-Original-To: dnsop@mail2.ietf.org Delivered-To: dnsop@mail2.ietf.org Received: from localhost (localhost [127.0.0.1]) by mail2.ietf.org (Postfix) with ESMTP id DDDC7A7B9AC9 for ; Wed, 14 Jan 2026 11:46:00 -0800 (PST) X-Virus-Scanned: amavisd-new at ietf.org X-Spam-Flag: NO X-Spam-Score: -1.899 X-Spam-Level: X-Spam-Status: No, score=-1.899 tagged_above=-999 required=5 tests=[BAYES_00=-1.9, RCVD_IN_VALIDITY_RPBL_BLOCKED=0.001, RCVD_IN_VALIDITY_SAFE_BLOCKED=0.001, SPF_PASS=-0.001] autolearn=ham autolearn_force=no Received: from mail2.ietf.org ([166.84.6.31]) by localhost (mail2.ietf.org [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id he2VGqUMrRNX for ; Wed, 14 Jan 2026 11:46:00 -0800 (PST) Received: from mycre.ws (mycre.ws [45.33.102.105]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (P-256) server-digest SHA256) (No client certificate requested) by mail2.ietf.org (Postfix) with ESMTPS id 990DCA7B9AC4 for ; Wed, 14 Jan 2026 11:46:00 -0800 (PST) Received: by gargantua.mycre.ws (Postfix, from userid 1000) id 683FE23066; Wed, 14 Jan 2026 14:45:54 -0500 (EST) Date: Wed, 14 Jan 2026 14:45:54 -0500 From: Robert Edmonds To: Petr =?utf-8?B?xaBwYcSNZWs=?= Message-ID: References: <9175DF63-77F9-4B4C-9EA9-76B30F941F84@strandkip.nl> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: Message-ID-Hash: DUYI6DMDEA5PXTMCMLU26QGIOUF4U7BC X-Message-ID-Hash: DUYI6DMDEA5PXTMCMLU26QGIOUF4U7BC X-MailFrom: edmonds@mycre.ws X-Mailman-Rule-Misses: dmarc-mitigation; no-senders; approved; emergency; loop; banned-address; member-moderation; header-match-dnsop.ietf.org-0; nonmember-moderation; administrivia; implicit-dest; max-recipients; max-size; news-moderation; no-subject; digests; suspicious-header CC: dnsop@ietf.org X-Mailman-Version: 3.3.9rc6 Precedence: list Subject: =?utf-8?q?=5BDNSOP=5D_Re=3A_ordering_of_RRSets_in_the_answer_section_of_a_DN?= =?utf-8?q?S_response?= List-Id: IETF DNSOP WG mailing list Archived-At: List-Archive: List-Help: List-Owner: List-Post: List-Subscribe: List-Unsubscribe: Petr Špaček wrote: > Is it 'protocol-legal' to have multiple identical RRs in the message? > > I would think it is not, but also I don't see test prohibiting it. "...servers should suppress such duplicates if encountered." (RFC 2181, Section 5) "A Resource Record Set should only be included once in any DNS reply. It may occur in any of the Answer, Authority, or Additional Information sections, as required. However it should not be repeated in the same, or any other, section, except where explicitly required by a specification." (RFC 2181, Section 5.5) -- Robert Edmonds