From sendmail  Tue May 21 08:45:01 2002
From: Eric Devolder <edevolder () eft ! be>
Date: Tue, 21 May 2002 08:45:01 +0000
To: sendmail
Subject: extended FEATURE for dnsbl : allowing to use mirror DNS sites
X-MARC-Message: https://marc.info/?l=sendmail&m=102244752115682
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Hello there.

The well-known dnsbl feature is quite interesting, but a problem arise when 
the NS server is a mirror.

Example: let's say that BL1.NET is the primary NS, and B2.ORG one of its 
mirror.

by using the feature with the mirror site, it will not work as the basic 
feature will append the mirror domain name to the query, not the original 
server one.

Here follows a revised dnsbl() feature (which I named dnsbl_mirror), for 
testing. However, the best would be to directly add the features to dnsbl 
itself.

Any comments are appreciated.

edevolder@anti-spam-remove-me.eft.be

(don't forget to remove the header in the domain address )




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divert(-1)
#
# Copyright (c) 1998, 1999 Sendmail, Inc. and its suppliers.
#	All rights reserved.
#
# By using this file, you agree to the terms and conditions set
# forth in the LICENSE file which can be found at the top level of
# the sendmail distribution.
#
#

divert(0)
ifdef(`_DNSBL_R_',`dnl',`dnl
VERSIONID(`$Id: dnsbl_mirror.m4,v 8.18.16.1 2000/11/22 01:13:21 ca Exp $')')
divert(-1)
define(`_DNSBL_SRV_', `ifelse(len(X`'_ARG_),`1',`blackholes.mail-abuse.org',_ARG_)')dnl
define(`_DNSBL_SFX_', `ifelse(len(X`'_ARG2_),`1',`_DNSBL_SRV_',_ARG2_)')dnl
define(`_DNSBL_MSG_', `ifelse(len(X`'_ARG3_),`1',`"550 Mail from " $`'&{client_addr} " refused by blackhole site '_DNSBL_SFX_`"',`_ARG3_')')dnl
divert(8)
# DNS based IP address spam list _DNSBL_SRV_
R$*			$: $&{client_addr}
R::ffff:$-.$-.$-.$-	$: <?> $(host $4.$3.$2.$1._DNSBL_SFX_. $: OK $)
R$-.$-.$-.$-		$: <?> $(host $4.$3.$2.$1._DNSBL_SFX_. $: OK $)
R<?>OK			$: OKSOFAR
R<?>$+			$#error $@ 5.7.1 $: _DNSBL_MSG_
divert(-1)

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