From owner-freebsd-hackers Mon May 20 12:59: 0 2002 Delivered-To: freebsd-hackers@freebsd.org Received: from pintail.mail.pas.earthlink.net (pintail.mail.pas.earthlink.net [207.217.120.122]) by hub.freebsd.org (Postfix) with ESMTP id E497437B404 for ; Mon, 20 May 2002 12:58:41 -0700 (PDT) Received: from pool0335.cvx40-bradley.dialup.earthlink.net ([216.244.43.80] helo=mindspring.com) by pintail.mail.pas.earthlink.net with esmtp (Exim 3.33 #2) id 179tIX-0003wV-00; Mon, 20 May 2002 12:58:25 -0700 Message-ID: <3CE95543.122D22FF@mindspring.com> Date: Mon, 20 May 2002 12:57:55 -0700 From: Terry Lambert X-Mailer: Mozilla 4.7 [en]C-CCK-MCD {Sony} (Win98; U) X-Accept-Language: en MIME-Version: 1.0 To: Damon Anton Permezel Cc: freebsd-hackers@freebsd.org Subject: Re: 4.6-* sendmail misfeatures References: <20020520105154.E962@damon.com> Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Sender: owner-freebsd-hackers@FreeBSD.ORG Precedence: bulk List-ID: List-Archive: (Web Archive) List-Help: (List Instructions) List-Subscribe: List-Unsubscribe: X-Loop: FreeBSD.ORG Damon Anton Permezel wrote: > Further investigation dug up this manifesto in the sendmail README: > > When attempting to canonify a hostname, some broken name > servers will return SERVFAIL (a temporary failure) on T_AAAA > (IPv6) lookups. If you want to excuse this behavior, include > WorkAroundBrokenAAAA in ResolverOptions. However, instead, > we recommend catching the problem and reporting it to the > name server administrator so we can rid the world of broken > name servers. > > So, in violation of the networking "be liberal in what you accept and > conservative in what you produce", sendmail in it's new form will have many > perplexed sysadmins spending lots of time tracking down these mysterious > failures. > > I suggest that the version of sendmail configs shipped with FreeBSD > should default to having WorkAroundBrokenAAAA set by default. FreeBSD has a history of enabling T/TCP by default (among other RFC compliance TCP options in the rc.conf), which originally broke things like Livingston Portmasters (which tended to respond, incorrectly, with "Christmas Tree" packets). I don't think it's incorrect to do this, so long as you are in strict compliance with the RFC's. I don't think "Be conservative in what you produce" was intended to promote the use of down-rev protocols. If I were similarly "conservative in what you produce" when it came to HTTP clients, then I would ver support HTTPS, since I would always conservatively try HTTP first. If the "workaround" disables IPv6 support, then it is no workaround (IMO). -- Terry To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-hackers" in the body of the message