Date: Thu, 24 Jul 1997 10:39:20 -0700 From: "jfesler@calweb.com" <jflists@calweb.com> To: Anthony.Kimball@East.Sun.COM, current@FreeBSD.ORG Subject: Re: (over)zealous mail bouncing Message-ID: <3.0.3.32.19970724103920.0094c100@pop.calweb.com> In-Reply-To: <199707241601.LAA03086@compound.east.sun.com> References: <199707241422.HAA00957@hub.freebsd.org>
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At 11:01 AM 7/24/97 -0500, Tony Kimball wrote: >I beg to differ. Most machines which may validly receive email do *not* >have valid hostnames. Using the majority-minority rule, *you* lose. >That's reality. Um - MX records. The host names in the email addresses, should have valid MX records, and as a fallback, a valid A record (preferably MX records though). Otherwise, the email address in question is non-replyable. And if it's non-replyable, it's not acceptable either. We actively block any SMTP session where the MAIL FROM: command lacks a valid DNS entry. If it takes >3 seconds to resolve, we assume it's slow/unreachable DNS. If it takes <3 seconds to resolve, we fail it immediately with no retrys, as in every case it's either a bad hostname, fake domain name, or a typo on someone's host portion of an email address. In every case, the error message says to contact postmaster@calweb.com for assistance, which is immune to the filter. Even UUCP sites are safe from our filter - they have MX records pointing to valid MX receivers that will take mail for their domain names.. -- Jason Fesler jfesler@calweb.com 'whois jf319' | When the chips are down Admin, CalWeb Internet Services www.calweb.com | The buffalo's empty Junk email returned in bulk; 1 cc to your postmaster | Junk mail probs? http://www.gigo.com/junkmail.htm | :-)
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