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rblcheck 1.5 - Command-line interface to RBL-style filters.
Copyright (C) 1997, 1998, 1999, 2000, 2001 Edward S. Marshall <>

This program is free software; you can redistribute it and/or modify it
under the terms of the GNU General Public License as published by the Free
Software Foundation; either version 2 of the License, or (at your option)
any later version.

This program is distributed in the hope that it will be useful, but
WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
for more details.

You should have received a copy of the GNU General Public License along
with this program; if not, write to the Free Software Foundation, Inc.,
675 Mass Ave, Cambridge, MA 02139, USA.


This program is a very basic interface to DNS listings such as the RBL
filter operated by the MAPS project. The basic idea of the filter is that
when someone is listed (for example, a blacklist for email abusers), a new
domain name is resolved of the form "", where is the abusive IP address in reverse (for example,
would be the IP address, and "" is the base
domain name of the filtering service (such as "",
for the MAPS project RBL filter).

To learn how to build this program, please read docs/INSTALL. Seriously.

rblcheck has only been tested by the author under Red Hat Linux 7.0,
Debian Linux 2.2r2, and Solaris 7, but there is no reason why it shouldn't
work on other platforms, assuming a working resolver library exists (the
one from BIND will work perfectly if your operating system does not supply
a libresolv). Please see docs/PLATFORMS for more platforms that we think 
might work.

For more information about RBL-style blacklists, please see the "sites.h"
file, which contains pointers to several RBL-alike listings, or refer to
era eriksson's list at .

The official home for rblcheck is . Any
ideas, bugfixes, porting notes, or requests for pizza delivery directions
should be sent to the rblcheck mailing list; please see the subscription 
page at .

Edward S. Marshall <>