Date: Mon, 17 Mar 2003 08:12:56 -0500 From: Bill Moran <wmoran@potentialtech.com> To: Len Conrad <LConrad@Go2France.com> Cc: freebsd-questions@freebsd.org Subject: Re: Sending mail to this list Message-ID: <3E75C9D8.7000704@potentialtech.com> In-Reply-To: <5.2.0.9.0.20030317062946.01d82870@mail.go2france.com> References: <48294587-583E-11D7-A325-000393BF3DE2@nmu.edu> <48294587-583E-11D7-A325-000393BF3DE2@nmu.edu> <5.2.0.9.0.20030317062946.01d82870@mail.go2france.com>
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en Conrad wrote: > >> 1) The name the mailserver announces in it's HELO line must resolve via >> forward DNS. It doesn't matter to what, it just has to resolve. >> 2) The IP of the server must reverse resolve to something, it doesn't >> matter to what: except that that name is then tested on a forward >> DNS check, which must work. This is actually in the FAQ: http://www.freebsd.org/doc/en_US.ISO8859-1/books/faq/misc.html#FREEBSD-MAIL-BOUNCES >> My understanding is that these simple tests block thousands of spam >> emails per second! > > per hour, not per second. Either way ... pretty good statistics. >> The most common mistake I've seen people make is to add multiple reverse >> DNS records (when the machine has multiple forward DNS records) Most >> DNS servers will allow you to do this, but it doesn't work. > > DNS works fine having a set of PTR records per ip. What doesn't work is > that applications that query for PTR records only use the physically > first PTR record returned in the DNS responce packet, which, due to > caching, is uncontrollable. Which means that the system (effectively) doesn't work with multiple PTR records, which was all I was trying to say. -- Bill Moran Potential Technologies http://www.potentialtech.com To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-questions" in the body of the message
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