From owner-freebsd-hackers Mon May 20 8:52: 2 2002 Delivered-To: freebsd-hackers@freebsd.org Received: from damon.com (damon.com [199.98.84.130]) by hub.freebsd.org (Postfix) with ESMTP id 1958437B400 for ; Mon, 20 May 2002 08:51:57 -0700 (PDT) Received: from damon.com (localhost [127.0.0.1]) by damon.com (8.12.3/8.12.3) with ESMTP id g4KFpsH4002369 for ; Mon, 20 May 2002 10:51:54 -0500 (CDT) (envelope-from dap@damon.com) Received: (from dap@localhost) by damon.com (8.12.3/8.12.3/Submit) id g4KFpswV002368 for freebsd-hackers@freebsd.org; Mon, 20 May 2002 10:51:54 -0500 (CDT) (envelope-from dap) Date: Mon, 20 May 2002 10:51:54 -0500 From: Damon Anton Permezel To: freebsd-hackers@freebsd.org Subject: 4.6-* sendmail misfeatures Message-ID: <20020520105154.E962@damon.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline User-Agent: Mutt/1.2.5.1i 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 Since upgrading from 4.5 to 4.6-*, I have had problems exchanging email with a correspondent at "austinenergy.com". It shows up as: % echo hi | mail -v no.such.user@austinenergy.com austinenergy.com: Name server timeout no.such.user@austinenergy.com... Transient parse error -- message queued for future delivery no.such.user@austinenergy.com... queued I have tracked this down to the fact that sendmail is using a IPv6-style lookup request. It is a "AAAA ?" rather than a "A ?" (in tcpdump-esque). 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. -- -- Damon Permezel dap@damon.com To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-hackers" in the body of the message