Date: Mon, 20 May 2002 12:57:55 -0700 From: Terry Lambert <tlambert2@mindspring.com> To: Damon Anton Permezel <dap@damon.com> Cc: freebsd-hackers@freebsd.org Subject: Re: 4.6-* sendmail misfeatures Message-ID: <3CE95543.122D22FF@mindspring.com> References: <20020520105154.E962@damon.com>
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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
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