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Date: Tue, 13 May 1997 18:43:11 -0700 (PDT)
From: Dan Busarow <dan@dpcsys.com>
To: John Beukema <john@packfish.gateway.net.hk>
cc: freebsd-isp@FreeBSD.ORG
Subject: Re: Sendmail hack
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On Mon, 12 May 1997, John Beukema wrote:
> How do you stop spammers who use an existing address which is not theirs?
> jbeukema

The latest check_rcpt at

	http://www.informatik.uni-kiel.de/%7Eca/email/check.html#check_rcpt

gets the sender's IP address.  If you add one file

F{SpamIP} /etc/sendmail.spamip

and one more test

R$={SpamIP}$* $| $*		$#error $@ 5.7.1 $: Spammer access denied

you can add entries to sendmail.spamip to block known spammers
by IP address or IP prefix.

It's harder for them to fake their IP address and IP addresses tend
to last longer than domain names for spammers so this really helps.

Add the R$={Spam ... right after the LocalIP test and F{SpamIP} right
after F{LocalIP}

Dan
-- 
 Dan Busarow                                                  714 443 4172
 DPC Systems / Beach.Net                                    dan@dpcsys.com
 Dana Point, California  83 09 EF 59 E0 11 89 B4   8D 09 DB FD E1 DD 0C 82