From owner-freebsd-questions Sun May 6 16:59: 5 2001 Delivered-To: freebsd-questions@freebsd.org Received: from nameserver.austclear.com.au (nameserver.austclear.com.au [192.83.119.132]) by hub.freebsd.org (Postfix) with ESMTP id CA49D37B422 for ; Sun, 6 May 2001 16:58:56 -0700 (PDT) (envelope-from ahl@austclear.com.au) Received: from tungsten.austclear.com.au (tungsten.austclear.com.au [192.168.70.1]) by nameserver.austclear.com.au (8.9.3/8.9.3) with ESMTP id JAA26524; Mon, 7 May 2001 09:58:52 +1000 (EST) Received: from tungsten (tungsten [192.168.70.1]) by tungsten.austclear.com.au (8.9.3/8.9.3) with ESMTP id JAA00759; Mon, 7 May 2001 09:58:52 +1000 (EST) Message-Id: <200105062358.JAA00759@tungsten.austclear.com.au> X-Mailer: exmh version 2.1.1 10/15/1999 To: Edwin Groothuis Cc: Wayne Pascoe , freebsd-questions@FreeBSD.ORG Subject: Re: Purpose of serial number in zone files (BIND) In-Reply-To: Message from Edwin Groothuis of "Fri, 04 May 2001 17:40:15 +0200." <20010504174015.F50786@d9168.upc-d.chello.nl> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Date: Mon, 07 May 2001 09:58:52 +1000 From: Tony Landells Sender: owner-freebsd-questions@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.ORG edwin@mavetju.org said: > DNS servers which are not authorative for a zone do not have the SOA > field, they only have the Time To Live for that single record. I agree with Edwin, the Serial Number in the SOA is ONLY used between master and slave servers to arrange synchronisation of zones. All other servers use the TTL on the record to decide how long a record is valid if they received a positive response. Later versions of BIND will also cache (authoritative) negative responses (for a comparatively short time, but it avoids sending a constant stream of queries when the authoritative server has already stated that there is no data). If they use the SOA then they are non-standard. Tony -- Tony Landells Senior Network Engineer Ph: +61 3 9677 9319 Australian Clearing Services Pty Ltd Fax: +61 3 9677 9355 Level 4, Rialto North Tower 525 Collins Street Melbourne VIC 3000 Australia To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-questions" in the body of the message