Date: Fri, 28 Nov 1997 00:04:04 -0600 (CST) From: Joel Ray Holveck <joelh@gnu.org> To: jkh@time.cdrom.com Cc: grog@lemis.com, jmb@FreeBSD.ORG, chat@hub.freebsd.org Subject: Re: major push by spammers? Message-ID: <199711280604.AAA00737@detlev.UUCP> In-Reply-To: <18154.880528164@time.cdrom.com> (jkh@time.cdrom.com) References: <18154.880528164@time.cdrom.com>
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> 2 ways: The first, if reverse DNS lookup fails, accounts for about 90% > of the rejects. When I first started doing this, I worried that > perhaps I was rejecting some legit emails so for the first couple of > weeks I'd do one day on, one day off. In 14 days worth of testing, I > got one "legitimate" message (though it was unanswerable due to said > misconfiguration, so I could have done without it :) and many many > hundreds of spams on the days that I had reverse DNS checking > disabled. Needless to say, I can't even imagine not having it on now. Now tell me, how does the reverse DNS lookup work? Does it perform a reverse DNS against the IP source vs. the line sent in EHLO, or what? -- Joel Ray Holveck - joelh@gnu.org - http://www.wp.com/piquan Fourth law of programming: Anything that can go wrong wi sendmail: segmentation violation - core dumped
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